some fixes + template support

Ticket: CM-1438
Reviewed By:
Testing Done:

This patch adds support for mako style templates.

Example:
% for v in [20,30,40]:
auto vlan${v}
    iface vlan${v} inet static
    address 10.20.${v}.3/24
    mstpctl_ports  glob swp1-52.${v}
    mstpctl_stp on
% endfor

open items:
    - currently templates will only work if python-mako is installed
      (Its apt-gettable from debian wheezy).

pkg/ifupdownmain.py

@@ -259,7 +259,7 @@ class ifupdownMain():
                         continue
                     dlist = module.get_dependent_ifacenames(ifaceobj,
                                     self.ifaceobjdict.keys())
-                    if dlist:
+                    if dlist is not None:
                         self.logger.debug('%s: ' %ifaceobj.get_name() +
                                 'got dependency list: %s' %str(dlist))
                         break