cogl-vertex-attribute: Optionally avoid applying the legacy state

cogl-vertex-attribute: Optionally avoid applying the legacy state

When an item is added to the journal the current pipeline immediately
gets the legacy state applied to it and the modified pipeline is
logged instead of the original. However the actual drawing from the
journal is done using the vertex attribute API which was also applying
the legacy state. This meant that the legacy state used would be a
combination of the state set when the journal entry was added as well
as the state set when the journal is flushed. To fix this there is now
an extra CoglDrawFlag to avoid applying the legacy state when setting
up the GL state for the vertex attributes. The journal uses this flag
when flushing.