- Fixed uninitialized variable in case GL_MAX_VERTEX_SHADER_STORAGE_BLOCKS does not exist.

Old graphics, like mine (Intel Sandybridge Mobile, GL 3.0 Mesa) do not support this, therefore most of the time RFL_SHADER_STORAGE_BUFFER wasn't unset (I found no consequence of this on my machine, but better safe than sorry).

Found out by Valgrind. (patch by edward-san)

src/gl/system/gl_interface.cpp

@@ -265,7 +265,7 @@ void gl_LoadExtensions()
 
 			// Mesa implements shader storage only for fragment shaders.
 			// Just disable the feature there. The light buffer may just use a uniform buffer without any adverse effects.
-			int v;
+			int v = 0;
 			glGetIntegerv(GL_MAX_VERTEX_SHADER_STORAGE_BLOCKS, &v);
 			if (v == 0)
 				gl.flags &= ~RFL_SHADER_STORAGE_BUFFER;