No need to call memset after wmalloc

memset is the last function call in wmalloc, just before it returns the
newly allocated memory.  Therefore it is not needed to call it again
after wmalloc call.  Although I would prefer to switch wmalloc to a
calloc-based wcalloc function, the compatibility of WINGs for old apps
should be kept.

util/wmsetbg.c

@@ -277,7 +277,6 @@ BackgroundTexture *parseTexture(RContext * rc, char *text)
 	}
 
 	texture = wmalloc(sizeof(BackgroundTexture));
-	memset(texture, 0, sizeof(BackgroundTexture));
 
 	GETSTRORGOTO(val, type, 0, error);