Support for the "p4 move" command was added in 8e9497c2 (git p4:
add support for 'p4 move' in P4Submit, 2012-07-12), which checks
to make sure that the client and server support the command.

But older versions of p4d may not handle the "-k" argument, and
newer p4d allow disabling "p4 move" with a configuration setting.
Check for both these cases by testing a p4 move command on bogus
filenames and looking for strings in the error messages.
Reported-by: NVitor Antunes <vitor.hda@gmail.com>
Signed-off-by: NPete Wyckoff <pw@padd.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>