release.sh: copy version files to rsrc

Otherwise, an "unknown" version number is created.

This regression was caused by the recent optimisation
that reduces the amount of extra work done by init.sh
on child instances of xbmk.

As a result of those changes, now release.sh has to
do some minor initialisation of its own, such as this.

Signed-off-by: Leah Rowe <leah@libreboot.org>

include/release.sh

@@ -27,6 +27,8 @@ release()
 
 	remkdir "$vdir"
 	x_ git clone . "$rsrc"
+	x_ cp ".version" "$rsrc/.version"
+	x_ cp ".versiondate" "$rsrc/.versiondate"
 
 	prep_release src
 	prep_release tarball