chg: dev: [postgres,apache] action are not anymore executed from the charm's root.

With version of ``0k-charm`` >= 0.3.0, actions script are not anymore
executed from charm's root : they stay in current directory.

apache/actions/load

@@ -41,7 +41,7 @@ if [ -z "$DOMAIN" ]; then
 fi
 
 
-. lib/common
+. "$CHARM_PATH"/lib/common
 
 set -e
 

postgres/actions/load

@@ -51,7 +51,7 @@ if [[ "$dbname" == *"@"* ]]; then
     IFS="@" read user dbname < <(echo "$dbname")
 fi
 
-. lib/common
+. "$CHARM_PATH/lib/common"
 
 ## This can work only if ~/.pgpass is correctly created by init.