There is no need to prevent iscsictl from adding iSER session when there
is no iSER support in ctld and/or kernel; should the user make that mistake,
the output from "iscsictl -L" is enough to determine what the problem is.

Sponsored by:	The FreeBSD Foundation
Added a regression test for r234131.

Discussed with:	 asomers
Sponsored by:	EMC / Isilon storage division