Add dependency hidden on router_interface

This patch adds hidden dependency for FloatingIPAssocoation resource on
RouterInterface resource.

Change-Id: I58a94318d10721e6c0eb582cdbaf489da85b8a8e
Closes-Bug: #1399702
Use only FIP dependencies from graph

This patch contains follow important changes:
 - Fix wrong parameter passsed in graph method.
 - Now we use only FIP dependencies from graph.
 - Tests were fixed according to correct logic. Previously we try to add
   router interface to FIP dependecies, when FIPAssociation was defined
   in template. It was incorrect, because in this case such dependecy
   should be added to FIPAssociation insteaf of FIP resource.

Change-Id: I0ee15b80627783fc2a4c037060629e3c2f364b82
Closes-Bug: #1399713
Add dependency on Router External Gateway property

FIP has dependecy for RouterGateway resource, but it was deperecated in
favor of Router property. So we should add corrsponding dependency for
FIP resource.

Change-Id: I5c45ddc96b17bb1f87188ae3e9aabf74e6e29e1d
Closes-Bug: #1399699
Merge "Add dependency hidden on router_interface"
Merge "Use only FIP dependencies from graph"
Merge "Add dependency on Router External Gateway property"