Avoid overaggressive chmod/chown on upgrade

It's reasonable for someone to change one or more of these directory
permissions after installation.  We shouldn't touch more than we need
on upgrade.  Each directory needs to be owned by the freeswitch user,
but past that we can leave discretion to the system administrator.

debian/freeswitch.postinst

@@ -22,9 +22,12 @@ case "$1" in
       /var/log/freeswitch \
       /var/run/freeswitch;
     do
-      mkdir -p $x
-      chown -R freeswitch:freeswitch $x
-      chmod -R o-rwx,g+u $x
+      if ! test -d $x; then
+        mkdir -p $x
+        chown freeswitch:freeswitch $x
+        chmod o-rwx,g+u $x
+      fi
+      chown freeswitch $x
     done
     ;;
   abort-upgrade|abort-remove|abort-deconfigure)