Add '+' sign at the end of echo package

Summary:
-Fix lldb test failures introduced by r238530
-This fix TestGdbRemoteAuxvSupport.py and TestLldbGdbServer.py

Test Plan:
./dotest -p TestGdbRemoteAuxvSupport.py
./dotest -p TestLldbGdbServer.py

Reviewers: clayborg, chaoren, vharron

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D10116

llvm-svn: 238535
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
index 37aed54..c61d9f4 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
@@ -917,7 +917,7 @@
     response.PutCString (";QStartNoAckMode+");
     response.PutCString (";QThreadSuffixSupported+");
     response.PutCString (";QListThreadsInStopReply+");
-    response.PutCString (";qEcho");
+    response.PutCString (";qEcho+");
 #if defined(__linux__)
     response.PutCString (";qXfer:auxv:read+");
 #endif