rev-parse: clear --exclude list after 'git rev-parse --all'

rev-parse: clear --exclude list after 'git rev-parse --all'

Commit [1] added the --exclude option to revision.c.  The --all,
--branches, --tags, --remotes, and --glob options clear the exclude
list.  Shortly therafter, commit [2] added the same to 'git rev-parse',
but without clearing the exclude list for the --all option.

[1] e7b432c52 ("revision: introduce --exclude=<glob> to tame wildcards", 2013-08-30)
[2] 9dc01bf06 ("rev-parse: introduce --exclude=<glob> to tame wildcards", 2013-11-01)

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>