default_postinst() fix wrong call of group_add

[base-files] default_postinst() fix wrong call of group_add
after 12bae65d07d29854204715cebc1ef1eae237fd9b group_add is
always called. shell scripting can be tricky...

wrong call:
[ -n "$gid" ] && group_exists $name || group_add $name $gid

this leads to a call of 'group_add' when $gid is emtpy, proof:

root@box:~ functionA() { echo A; }
root@box:~ functionB() { echo B; }
root@box:~ VAR=
root@box:~ [ -n "$VAR" ] && functionA || functionB
B
root@box:~ # functionB was called, but VAR is not filled
root@box:~ VAR=filled
root@box:~ [ -n "$VAR" ] && functionA || functionB
A

Signed-off-by: Bastian Bittorf <bittorf@bluebottle.com>

SVN-Revision: 42926

package/base-files/files/lib/functions.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
-# Copyright (C) 2006-2013 OpenWrt.org
+# Copyright (C) 2006-2014 OpenWrt.org
 # Copyright (C) 2006 Fokus Fraunhofer <carsten.tittel@fokus.fraunhofer.de>
 # Copyright (C) 2010 Vertical Communications
 
@@ -193,7 +193,10 @@ default_postinst() {
 				}
 
 				gid=$id
-				[ -n "$gid" ] && group_exists $name || group_add $name $gid
+				[ -n "$gid" ] && {
+					group_exists $name || group_add $name $gid
+				}
+
 				[ -z "$gid" ] && {
 					group_add_next $name
 					gid=$?