Backport revision 429223 from Asterisk 13

Backport revision 429223 from Asterisk 13

The bug fixed by that patch exists in Asterisk 11 as
well, so the fix should be applied there.

When connecting to a remote Asterisk console, the buffer
used to read the initial hostname/pid/version from the
main Asterisk process did not ensure the input was
NULL-terminated, and the buffer was small for certain
use cases. This patch expands the buffer to be 256
bytes and ensures the input it reads is NULL-terminated.

ASTERISK-21854 #close
Reported by klaus3000

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@433919 65c4cc65-6c06-0410-ace0-fbb531ad65f3