repack: do not fall back to incremental repacking with [-a|-A]

When repack is called with either the -a or -A option, the user has
requested to repack all objects including those referenced by the
alternates mechanism. Currently, if there are no local packs without
.keep files, then repack will call pack-objects with the
'--unpacked --incremental' options which causes it to exclude alternate
packed objects. So, remove this fallback.

Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-repack.sh

@@ -71,13 +71,10 @@ case ",$all_into_one," in
 				existing="$existing $e"
 			fi
 		done
-	fi
-	if test -z "$args"
-	then
-		args='--unpacked --incremental'
-	elif test -n "$unpack_unreachable"
-	then
-		args="$args $unpack_unreachable"
+		if test -n "$args" -a -n "$unpack_unreachable"
+		then
+			args="$args $unpack_unreachable"
+		fi
 	fi
 	;;
 esac