vbo: Don't discount stride == 0 for testing all varyings in VBOs.

In fixed function, stride == 0 (e.g. glColor4f() outside of the draw
call) would get turned into uniform inputs, which is why it was
ignored originally in this test.  For shaders, drivers end up seeing a
need to upload stride == 0 data, and get confused by needing to upload
when vbo_all_varyings_in_vbos() returned true.  In the 965 driver
case, it wouldn't bother to compute the min/max index, and uploaded
nothing if the min/max wasn't known.

We've talked about removing the ff stride=0-into-uniforms code, so
this check shouldn't be missed once that's gone.

Fixes ARB_vertex_buffer_object/mixed-immediate-and-vbo
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=37934
Reviewed-by: Brian Paul <brianp@vmware.com>

src/mesa/vbo/vbo_rebase.c

@@ -78,8 +78,7 @@ GLboolean vbo_all_varyings_in_vbos( const struct gl_client_array *arrays[] )
    GLuint i;
    
    for (i = 0; i < VERT_ATTRIB_MAX; i++)
-      if (arrays[i]->StrideB &&
-	  arrays[i]->BufferObj->Name == 0)
+      if (arrays[i]->BufferObj->Name == 0)
 	 return GL_FALSE;
 
    return GL_TRUE;