Fix renderergl2 warnings

code/renderergl2/tr_shader.c

@@ -3692,7 +3692,7 @@ a single large text block that can be scanned for shader names
 static void ScanAndLoadShaderFiles( void )
 {
 	char **shaderFiles;
-	char *buffers[MAX_SHADER_FILES];
+	char *buffers[MAX_SHADER_FILES] = {NULL};
 	char *p;
 	int numShaderFiles;
 	int i;