update/release: delete multi-tree upstream repos

e.g. src/coreboot/coreboot must not appear in a release,
because we instead have directories like
src/coreboot/default or src/coreboot/cros

lbmk resets src/coreboot/coreboot to HEAD, but then resets
revisions properly in copies of it

therefore, for reproducibility, we must not include
src/coreboot/coreboot, src/u-boot/u-boot or
src/seabios/seabios into libreboot releases

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

script/update/project/release

@@ -93,6 +93,11 @@ fetch_trees()
 	for x in ${_f}; do
 		./update project trees -f "${x}" || err "${_xm}: fetch ${x}"
 	done
+	for x in config/*/build.list; do
+		[ -f "${x}" ] || continue
+		xp="${x#*/}"; xp="${xp%/*}"
+		[ -L "${xp}" ] || x_ rm -Rf "src/${xp}/${xp}"
+	done
 	rm -Rf */.git* */*/.git* */*/*/.git* */*/*/*/.git* */*/*/*/*/.git* \
 	    */*/*/*/*/*/.git* */*/*/*/*/*/*/.git* */*/*/*/*/*/*/*/.git* \
 	    .git || err "${_xm}: rm-dotgit"