Implement removeKeyPair

Bug: 22541933
Change-Id: I37317e7c22e89816156e6e9a7abf4c5a59e8440a
diff --git a/src/com/android/keychain/KeyChainService.java b/src/com/android/keychain/KeyChainService.java
index ee19e50..cd2ac84 100644
--- a/src/com/android/keychain/KeyChainService.java
+++ b/src/com/android/keychain/KeyChainService.java
@@ -174,6 +174,11 @@
             return true;
         }
 
+        @Override public boolean removeKeyPair(String alias) {
+            checkCertInstallerOrSystemCaller();
+            return Credentials.deleteAllTypesForAlias(mKeyStore, alias);
+        }
+
         private X509Certificate parseCertificate(byte[] bytes) throws CertificateException {
             CertificateFactory cf = CertificateFactory.getInstance("X.509");
             return (X509Certificate) cf.generateCertificate(new ByteArrayInputStream(bytes));