Add 5 time measurement points

run_process           process starting time
test_with_retry       process starting time (for neutron legacy)
restart_apache_server Apache HTTPD restart time
wait_for_service      HTTP server waiting time
git_timed             git command execution time

example

========================
DevStack Components Timed
========================

run_process - 52 secs
test_with_retry - 3 secs
apt-get-update - 8 secs
pip_install - 76 secs
restart_apache_server - 9 secs
wait_for_service - 11 secs
git_timed - 127 secs
apt-get - 15 secs

Change-Id: I66140726617450cd9fe9b702092cacf053a20065

lib/apache

@@ -185,9 +185,11 @@ function restart_apache_server {
     # Apache can be slow to stop, doing an explicit stop, sleep, start helps
     # to mitigate issues where apache will claim a port it's listening on is
     # still in use and fail to start.
+    time_start "restart_apache_server"
     stop_service $APACHE_NAME
     sleep 3
     start_service $APACHE_NAME
+    time_stop "restart_apache_server"
 }
 
 # Restore xtrace