remove powermockito tests for Java5 compatibility

the 1.6.x line of powermock is compiled with -target 1.6 and cannot be
used by our Java5 based build systems. powermock 1.5 is incompatible
with the version of JUnit we use.

I intend to start a vote about moving compress to Java6 after the 1.11
release - at which point the test will get added back.
diff --git a/pom.xml b/pom.xml
index ffc909e..8cba58e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -45,7 +45,6 @@
     <!-- configuration bits for cutting a release candidate -->
     <commons.release.version>${project.version}</commons.release.version>
     <commons.rc.version>RC1</commons.rc.version>
-    <powermock.version>1.6.4</powermock.version>
   </properties>
 
   <issueManagement>
@@ -66,18 +65,6 @@
       <version>1.5</version>
       <optional>true</optional>
     </dependency>
-    <dependency>
-      <groupId>org.powermock</groupId>
-      <artifactId>powermock-module-junit4</artifactId>
-      <version>${powermock.version}</version>
-      <scope>test</scope>
-    </dependency>
-    <dependency>
-      <groupId>org.powermock</groupId>
-      <artifactId>powermock-api-mockito</artifactId>
-      <version>${powermock.version}</version>
-      <scope>test</scope>
-    </dependency>
   </dependencies>
 
   <developers>
diff --git a/src/test/java/org/apache/commons/compress/archivers/sevenz/SevenZNativeHeapTest.java b/src/test/java/org/apache/commons/compress/archivers/sevenz/SevenZNativeHeapTest.java
deleted file mode 100644
index 896af8c..0000000
--- a/src/test/java/org/apache/commons/compress/archivers/sevenz/SevenZNativeHeapTest.java
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- *  Licensed to the Apache Software Foundation (ASF) under one or more
- *  contributor license agreements.  See the NOTICE file distributed with
- *  this work for additional information regarding copyright ownership.
- *  The ASF licenses this file to You under the Apache License, Version 2.0
- *  (the "License"); you may not use this file except in compliance with
- *  the License.  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- *  Unless required by applicable law or agreed to in writing, software
- *  distributed under the License is distributed on an "AS IS" BASIS,
- *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *  See the License for the specific language governing permissions and
- *  limitations under the License.
- *
- */
-package org.apache.commons.compress.archivers.sevenz;
-
-import org.apache.commons.compress.AbstractTestCase;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.mockito.InjectMocks;
-import org.mockito.Mockito;
-import org.powermock.api.mockito.PowerMockito;
-import org.powermock.core.classloader.annotations.PrepareForTest;
-import org.powermock.modules.junit4.PowerMockRunner;
-
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.InputStream;
-import java.io.OutputStream;
-import java.util.zip.Deflater;
-import java.util.zip.Inflater;
-
-@RunWith(PowerMockRunner.class)
-@PrepareForTest(Coders.DeflateDecoder.class)
-public class SevenZNativeHeapTest extends AbstractTestCase {
-
-    @InjectMocks
-    Coders.DeflateDecoder deflateDecoder;
-
-    @Test
-    public void testEndDeflaterOnCloseStream() throws Exception {
-        final Deflater deflater = PowerMockito.spy(new Deflater());
-        PowerMockito.whenNew(Deflater.class).withAnyArguments().thenReturn(deflater);
-
-        final OutputStream outputStream = deflateDecoder.encode(new ByteArrayOutputStream(), 9);
-        outputStream.close();
-
-        Mockito.verify(deflater).end();
-    }
-
-    @Test
-    public void testEndInflaterOnCloseStream() throws Exception {
-        final Inflater inflater = PowerMockito.spy(new Inflater());
-        PowerMockito.whenNew(Inflater.class).withAnyArguments().thenReturn(inflater);
-
-        final InputStream inputStream = deflateDecoder.decode("dummy",new ByteArrayInputStream(new byte[0]),0,null,null);
-        inputStream.close();
-
-        Mockito.verify(inflater).end();
-    }
-}