truncate Gemfile.lock always

debian/postinst

@@ -47,6 +47,7 @@ https://github.com/hyperic/sigar/issues/60 ..."
 
 	echo "Installing gems with rubygems ..."
 	su ${diaspora_user} -s /bin/sh -c "mkdir -p ~/vendor/bundle"
+	su ${diaspora_user} -s /bin/sh -c "touch ~/Gemfile.lock && truncate -s 0 ~/Gemfile.lock"
 	su ${diaspora_user} -s /bin/sh -c "bundle install --path vendor/bundle --with ${BUNDLE_WITH} --without development test"
         # Fix permissions (see #847286)
 	su ${diaspora_user} -s /bin/sh -c "find vendor/bundle -type f -exec chmod ga-w {} \;"