Set ai2 to NULL in in find_host() before the loop and after calling

Set ai2 to NULL in in find_host() before the loop and after calling
freeaddrinfo() on it to indicate that it doesn't point to a valid
addrinfo list.  This fixes this Coverity issues:
	1006368 Uninitialized pointer read
	1018506 Double free
	1305590 Resource leak
that can be triggered in the hp->hostname[0] != '\0' case.

Don't treat a character as a boolean.

Fix these Coverity issues:
	1009293 Unchecked return value from library
	1194246 Wrong size argument
by tweaking the status file extend code.

Reported by:	Coverity
CID:		1006368, 1018506, 1305590, 1009293, 1194246
Reviewed by:	rmacklem
Feedback from:	hrs
MFC after:	1 week
Differential Revision:	D6398