Fix a memory leak that showed up when we delete LUNs.  The memory used for
the LUN was never freed.

ctl.c:		Adjust ctl_alloc_lun() to make sure we don't clear the
		CTL_LUN_MALLOCED flag.

Reported by:	Sreenivasa Honnur <shonnur@chelsio.com>
Sponsored by:	Spectra Logic
MFC after:	3 days