bundle: remove stray single-quote from error message

bundle: remove stray single-quote from error message

After running rev-list --boundary to retrieve the list of boundary
commits, "git bundle create" runs its own revision walk.  If in this
stage git encounters an unfamiliar option, it writes a message with an
unbalanced quotation mark:

	error: unrecognized argument: --foo'

Drop the stray quote to match the "unrecognized argument: %s" message
used elsewhere and save translators some work.

This is mostly a futureproofing measure: for now, the "rev-list
--boundary" command catches most strange arguments on its own and the
above message is not seen unless you try something esoteric like "git
bundle create test.bundle --header HEAD".

Reported-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>