website-build: build.sh: fix offline builds.

Without that fix, build.sh compares the desired Untitled revision with
the GNU Boot git revision, so the comparison always fail, which leads
to broken offline builds.

This was broken from the start in the commit
cabc1cac08 ("website-build: avoid
unnecessary git fetch").

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
Acked-by: Adrien 'neox' Bourmault <neox@gnu.org>

website-build/build.sh

@@ -51,7 +51,8 @@ sync_repo()
 			git -C "${dst_path}" checkout "${src_revision}"
 		fi
 	elif [ -z "${src_path}" ] ; then
-		localrev="$(git --no-pager log --oneline HEAD -1 --format='%H')"
+		localrev="$(git -C "${dst_path}" --no-pager \
+				log --oneline HEAD -1 --format='%H')"
 
 		git -C "${dst_path}" remote get-url origin || \
 		    git -C "${dst_path}" remote add origin "${src_uri}"