functions-common: Use `systemctl` when applicable

We live in a new systemd world, use the native commands to talk to it
if available.

Change-Id: Iccdc35f0c9da2997f9e672bc1d24ca15d3403d98
diff --git a/functions-common b/functions-common
index d473077..9973d8f 100644
--- a/functions-common
+++ b/functions-common
@@ -2264,11 +2264,12 @@
 # Service wrapper to restart services
 # restart_service service-name
 function restart_service {
-    if is_ubuntu; then
-        sudo /usr/sbin/service $1 restart
+    if [ -x /bin/systemctl ]; then
+        sudo /bin/systemctl restart $1
     else
-        sudo /sbin/service $1 restart
+        sudo service $1 restart
     fi
+
 }
 
 # Only change permissions of a file or directory if it is not on an
@@ -2286,20 +2287,20 @@
 # Service wrapper to start services
 # start_service service-name
 function start_service {
-    if is_ubuntu; then
-        sudo /usr/sbin/service $1 start
+    if [ -x /bin/systemctl ]; then
+        sudo /bin/systemctl start $1
     else
-        sudo /sbin/service $1 start
+        sudo service $1 start
     fi
 }
 
 # Service wrapper to stop services
 # stop_service service-name
 function stop_service {
-    if is_ubuntu; then
-        sudo /usr/sbin/service $1 stop
+    if [ -x /bin/systemctl ]; then
+        sudo /bin/systemctl stop $1
     else
-        sudo /sbin/service $1 stop
+        sudo service $1 stop
     fi
 }