Verify verdat which is returned from malloc is not NULL.

Ensure we don't pass NULL to free.

Klocwork #306 (at least the first part, checking malloc)

Modules/rgbimgmodule.c

@@ -410,6 +410,11 @@ longimagedata(PyObject *self, PyObject *args)
 		addlongimgtag(base, xsize, ysize);
 #endif
 		verdat = (unsigned char *)malloc(xsize);
+		if (!verdat) {
+			Py_CLEAR(rv);
+			goto finally;
+		}
+
 		fseek(inf, 512, SEEK_SET);
 		for (z = 0; z < zsize; z++) {
 			lptr = base;
@@ -431,10 +436,14 @@ longimagedata(PyObject *self, PyObject *args)
 			copybw((Py_Int32 *) base, xsize * ysize);
 	}
   finally:
-	free(starttab);
-	free(lengthtab);
-	free(rledat);
-	free(verdat);
+	if (starttab)
+		free(starttab);
+	if (lengthtab)
+		free(lengthtab);
+	if (rledat)
+		free(rledat);
+	if (verdat)
+		free(verdat);
 	fclose(inf);
 	return rv;
 }