[gen][wiki][site_hardware] replace .append with '<<' to add in Array

The append method works fine with recent version of Ruby, however, we
still need to support old version of Ruby (2.1) to work with our Jenkins
tests suite.
Fixes: 3fd6236e

lib/refrepo/gen/wiki/generators/site_hardware.rb

@@ -391,21 +391,21 @@ def get_hardware(sites)
         hard['network_description'] = network_description.map do |e|
           desc = []
           if e['name'].nil? or e['name'] == e['device']
-            desc.append(e['device'])
+            desc << e['device']
           else
-            desc.append(e['device'] + "/" + e['name'])
+            desc << e['device'] + "/" + e['name']
           end
-          desc.append(e['interface'])
+          desc << e['interface']
 
           if !(e['unwired'] and e['unavailable_for_experiment'])
-            desc.append('configured rate: ' + (e['unwired'] ? 'n/c' : G5K.get_rate(e['rate'])))
+            desc << 'configured rate: ' + (e['unwired'] ? 'n/c' : G5K.get_rate(e['rate']))
           end
           if !(e['model'] == 'N/A N/A' and e['unavailable_for_experiment']) # don't include interface model if not available
             e['model'] = 'N/A' if e['model'] == 'N/A N/A'
-            desc.append('model: '+ e['model'])
+            desc << 'model: '+ e['model']
           end
-          desc.append('driver: ' + e['driver']) if e['driver']
-          desc.append('SR-IOV enabled') if e['sriov'] and not e['unavailable_for_experiment']
+          desc << 'driver: ' + e['driver'] if e['driver']
+          desc << 'SR-IOV enabled' if e['sriov'] and not e['unavailable_for_experiment']
           # Generate final string and then adjust
           s = desc.join(', ')
           if e['no_kavlan']