Misc Coverity fixes in camcontrol(8)

CID 1229913 Fix output of "camcontrol persist -i report_capabilities".

		The reported Persistent Reservation Types were wrong in all
		cases.

CID 1356029 Annotate the code so Coverity will know that this is a false

		positive.

CID 1366830 Fix a memory leak in "camcontrol timestamp -s"
CID 1366832 Fix a segfault that could be caused by bad drive firmware

Also, fix the man page entry for the "camcontrol epc state" command to match
what the code does.

Reviewed by: ken, wblock
MFC after: 4 weeks
Sponsored by: Spectra Logic Corp
Differential Revision: https://reviews.freebsd.org/D9239