* src/usermod.c (update_group, update_gshadow): Reduce complexity

and document checks. Some checks were always true/false within
	their call context.

ChangeLog

@@ -13,6 +13,9 @@
 	check if changes are needed.
 	* src/usermod.c: usage() does not return. Add annotations.
 	* src/usermod.c (update_gshadow): is_member was computed twice.
+	* src/usermod.c (update_group, update_gshadow): Reduce complexity
+	and document checks. Some checks were always true/false within
+	their call context.
 
 2011-07-08  Nicolas François  <nicolas.francois@centraliens.net>