Fixed an issue where even if the communication object had Clear() called on it, it could try and call through to an installed callback.
Fixed an issue where even if the communication object had Clear() called on
it, it could try and call through to an installed callback.



git-svn-id: b33bab8abb5b18c12ee100cd7761ab452d00b2b0@138146 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb