[SRCREV][SETUP-ENVIRONMENT] copy SRCREV.conf from custom layer if present
If there's a custom layer and it contains a conf/SRCREV.conf file, copy that file
instead of the one in the machine/architecture layers.
Also refactor some code.
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If there's a custom layer and it contains a conf/SRCREV.conf file, copy that file
instead of the one in the machine/architecture layers.
Also refactor some code.