Now that the command interpreter runs in a separate thread in Xcode, we need to lock the target API lock instead of trying to lock it.

What was happening was:
1 - Xcode ran and stopped and was doing work on thread 2
2 - Users would type something in Xcode console on thread 1
3 - thread 3 would be running command interpreter thread and try to execute command but get "failed to get API lock" error for any command that wanted the target API lock (like "expression")

<rdar://problem/15775016>

llvm-svn: 200997
diff --git a/lldb/source/Interpreter/CommandObject.cpp b/lldb/source/Interpreter/CommandObject.cpp
index c71ca28..c699536 100644
--- a/lldb/source/Interpreter/CommandObject.cpp
+++ b/lldb/source/Interpreter/CommandObject.cpp
@@ -261,13 +261,7 @@
         {
             Target *target = m_exe_ctx.GetTargetPtr();
             if (target)
-            {
-                if (m_api_locker.TryLock (target->GetAPIMutex(), NULL) == false)
-                {
-                    result.AppendError ("failed to get API lock");
-                    return false;
-                }
-            }
+                m_api_locker.Lock (target->GetAPIMutex());
         }
     }