Fencing: fix asset compilation

fixes BZ #1141522
Merge pull request #306 from ifarkas/fencing-fix_asset_compilation

Fencing: fix asset compilation
fixes BZ#1143047: set fencing to 'disabled' instead of '' when not available
refactor network query to simplify method calling
lib methods to return the interface and subnet for the gateway interface
Merge pull request #308 from sseago/fencing-disabled

fixes BZ#1143047: set fencing to 'disabled' instead of '' when not avail...
Merge pull request #309 from sseago/default-gateway

Default gateway