A small fixup needed for debugserver to work natively

on iOS devices; fallout from Vince's cleanups made
in r237218 back in May.  iOS native lldbs will call
StartDebugserverProcess() with a random port #
(see ProcessGDBRemote::LaunchAndConnectToDebugserver)
and neither side of this conditional expression should
be followed in that case.

I added an "if (in_port == 0) { ..." check around the
entire if/then/else and indented the block of code so
the diff looks larger than it really is.

<rdar://problem/21712643> 

llvm-svn: 248343