Fix being able to get a thread result when calling HostThreadPosix::Join(). It was broken when initially checked in by getting the thread result into a temporary variable and never doing anything with it. Most threads in LLDB don't look at their thread results, but launching processes in a terminal window on MacOSX does require getting a thread result and this broke "process launch --tty" on darwin.
Fix being able to get a thread result when calling HostThreadPosix::Join(). It was broken when initially checked in by getting the thread result into a temporary variable and never doing anything with it. Most threads in LLDB don't look at their thread results, but launching processes in a terminal window on MacOSX does require getting a thread result and this broke "process launch --tty" on darwin.

<rdar://problem/19308966>

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@225224 91177308-0d34-0410-b5e6-96231b3b80d8

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