Bind texture after setting buffer;

The `buffer` field was not being initialized to 0, so sometimes
the texture was binding to the wrong target.

src/graphics/texture.c

@@ -7,6 +7,7 @@ Texture* lovrTextureCreate(void* data, int size) {
   Texture* texture = malloc(sizeof(Texture));
   if (!texture) return NULL;
 
+  texture->buffer = 0;
   glGenTextures(1, &texture->id);
 
   if (data) {
@@ -24,8 +25,6 @@ Texture* lovrTextureCreate(void* data, int size) {
     free(image);
   }
 
-  texture->buffer = 0;
-
   return texture;
 }