Terminate an unused char* buffer correctly so we don't try to open
it later in GDBRemoteCommunication::StartDebugserverProcess and report
an error.
<rdar://problem/15820813> 


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@200047 91177308-0d34-0410-b5e6-96231b3b80d8