kernel-yocto: Ensure python code has awlays run before SRCPV is expanded
The python code in this class file needs to run before SRCPV is expanded
and calls into the fetcher are made. To so this we create a python function
and prepend a call to it before SRCPV's get_srcrev() call.
Ugly, ugly, ugly but the ordering is guaranteed.
If this doesn't happen, the fetcher can end up in two different states and
there may be caching implications of this.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
