The table is initialized on process attach, and should be freed on process
detach (which is where SECUR32_deinitSchannelSP gets called).

Two identical calls are made with the same parameters, and there are no
documented side effects of this function, so I removed one of them.

Using the ITextHost interface allows this notification to be received
for windowless richedit controls.  Windowed richedit conrols have an
ITextHost implementation that will fill in hwndFrom and idFrom, but
these should probably be initialized to 0 for windowless richedit
controls.

The situation the code tests for should never happen because either the
stateblock will still have a reference to the vertex declaration, or the
stateblock itself will be released.