Adopt clean-source-libs.sh to split sources

After 26994b156b just removing the
libraries/source directory will delete files under version control
needed to build the packages.

Use git clean instead to get back to a clean slate.

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

libraries/clean-source-libs.sh

@@ -1,7 +1,6 @@
 #!/bin/sh
 
-# This short script allows one to reset source libraries to a clean state without
-# having to redownload everything.
+# This short script allows one to reset source libraries to a clean state
 # (We don't attempt to clean up every last file here - output in binaries/system/
 # will still be there, etc. This is mostly just to quickly fix problems in the
 # bundled dependencies.)
@@ -11,11 +10,7 @@ cd "$(dirname "$0")" || exit 1
 
 echo "Cleaning bundled third-party dependencies..."
 
-if [ -e source/.svn ]; then
-	(cd source && svn revert -R . && svn st --no-ignore | cut -c 9- | xargs rm -rf)
-else
-	rm -rf source
-fi
+git clean -fx source
 
 echo
 echo "Done. Try running build-source-libs.sh again now."