Remove more superfluous if(p) checks around free(p)

This patch has been generated by the following Coccinelle semantic patch:

@@
expression E;
@@

-if(E) { free(E); }
+free(E);

Signed-off-by: Mikhail Gusarov <dottedmag@dottedmag.net>
Reviewed-by: Julien Cristau <jcristau@debian.org>
Reviewed-by: Fernando Carrijo <fcarrijo@yahoo.com.br>
Reviewed-by: Matt Turner <mattst88@gmail.com>

Xext/xace.c

@@ -323,7 +323,7 @@ XaceCensorImage(
 	     */
 	    memset(pBuf, 0, (int)(widthBytesLine * h));
 	}
-	if (pRects)     free(pRects);
+	free(pRects);
 	if (pScratchGC) FreeScratchGC(pScratchGC);
 	if (pPix)       FreeScratchPixmapHeader(pPix);
     }