“process launch” should “detach” not “kill” if the current process was one we attached to.

“process attach” should ask the same questions as process launch if there is a current process.
“process connect” then “process launch” or “process attach” should actually work.

<rdar://problem/13524210>
<rdar://problem/13524208>
<rdar://problem/13488919>

llvm-svn: 178324