support/String: Fix PVS 626

Fix memory leak when realloc() fails.

Change-Id: I5b44df57bdd251e5164938ed70412c909ce09df1
Reviewed-on: https://review.haiku-os.org/c/1004
Reviewed-by: Adrien Destugues <[email protected]>

src/kits/support/String.cpp

@@ -2360,9 +2360,14 @@ BString::_Resize(int32 length)
 	if (length < 0)
 		length = 0;
 
-	data = (char*)realloc(data, length + kPrivateDataOffset + 1);
+	char* newData = (char*)realloc(data, length + kPrivateDataOffset + 1);
-	if (data == NULL)
+	if (newData == NULL) {
+		free(data);
+		data = NULL;
 		return NULL;
+	} else {
+		data = newData;
+	}
 
 	data += kPrivateDataOffset;