Use double bracket test for consistency

etc/portage/repo.postsync.d/sync_gentoo_cache

@@ -3,13 +3,13 @@
 source /etc/init.d/functions.sh
 source /etc/portage/util-functions.sh
 
-repository_name=${1}
-repository_path=${3}
+repository_name="${1}"
+repository_path="${3}"
 
 # Number of jobs for egencache, default is number or processors.
 parallel_jobs="$(nproc)"
 
-if [ "${repository_name}" == "gentoo" ]; then
+if [[ ${repository_name} == "gentoo" ]]; then
 	ebegin "Fetching pre-generated metadata cache for ${repository_name}"
 	rsync -aq rsync://rsync.gentoo.org/gentoo-portage/metadata/md5-cache/ "${repository_path}"/metadata/md5-cache/
 	eend $?

etc/portage/repo.postsync.d/sync_gentoo_dtd

@@ -3,10 +3,10 @@
 source /etc/init.d/functions.sh
 source /etc/portage/util-functions.sh
 
-repository_name=${1}
-repository_path=${3}
+repository_name="${1}"
+repository_path="${3}"
 
-if [ "${repository_name}" == "gentoo" ]; then
+if [[ ${repository_name} == "gentoo" ]]; then
 	DTDDIR="${repository_path}"/metadata/dtd
 	ebegin "Updating DTDs"
 	if [[ -e ${DTDDIR} ]]; then

etc/portage/repo.postsync.d/sync_gentoo_glsa

@@ -3,10 +3,10 @@
 source /etc/init.d/functions.sh
 source /etc/portage/util-functions.sh
 
-repository_name=${1}
-repository_path=${3}
+repository_name="${1}"
+repository_path="${3}"
 
-if [ "${repository_name}" == "gentoo" ]; then
+if [[ ${repository_name} == "gentoo" ]]; then
 	GLSADIR="${repository_path}"/metadata/glsa
 	ebegin "Updating GLSAs"
 	if [[ -e ${GLSADIR} ]]; then

etc/portage/repo.postsync.d/sync_gentoo_herds_xml

@@ -3,10 +3,10 @@
 source /etc/init.d/functions.sh
 source /etc/portage/util-functions.sh
 
-repository_name=${1}
-repository_path=${3}
+repository_name="${1}"
+repository_path="${3}"
 
-if [ "${repository_name}" == "gentoo" ]; then
+if [[ ${repository_name} == "gentoo" ]]; then
 	ebegin "Updating herds.xml"
 	wget -q -O "${repository_path}"/metadata/herds.xml https://api.gentoo.org/packages/herds.xml
 	eend $?

etc/portage/repo.postsync.d/sync_gentoo_news

@@ -3,10 +3,10 @@
 source /etc/init.d/functions.sh
 source /etc/portage/util-functions.sh
 
-repository_name=${1}
-repository_path=${3}
+repository_name="${1}"
+repository_path="${3}"
 
-if [ "${repository_name}" == "gentoo" ]; then
+if [[ ${repository_name} == "gentoo" ]]; then
 	NEWSDIR="${repository_path}"/metadata/news
 	ebegin "Updating news items"
 	if [[ -e ${NEWSDIR} ]]; then