packages: dependencies: fix command line usage.

Without that fix, running ./resources/packages/dependencies/install
prints the help and does not do any dependency installation.

This was broken from the start in the commit
fe28bc3c82 ("dependencies: move into
single package.").

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
Acked-by: Adrien 'neox' Bourmault <neox@gnu.org>

resources/packages/dependencies/install

@@ -40,7 +40,7 @@ is_base_distro()
 if [ $# -eq 1 ] && [ "$1" == "--help" ] ; then
     usage "${progname}"
     exit 0
-else
+elif [ $# -ne 0 ] ; then
     usage "${progname}"
     exit ${EX_USAGE}
 fi