[nancy] add some warranty for networks equipements

input/grid5000/sites/nancy/networks/gw-nancy.yaml

 ---
 gw-nancy:
   model: Cisco Nexus 9508
+  warranty: 09.2020
   kind: router
   site: nancy
   snmp_community: public

input/grid5000/sites/nancy/networks/sgraphene1.yaml

 ---
 sgraphene1:
   model: 3com 4510G
+  warranty: 10.2014
   kind: switch
   site: nancy
   snmp_community: public

input/grid5000/sites/nancy/networks/sgraphene2.yaml

 ---
 sgraphene2:
   model: 3com 4510G
+  warranty: 10.2014
   kind: switch
   site: nancy
   snmp_community: public

input/grid5000/sites/nancy/networks/sgraphene3.yaml

 ---
 sgraphene3:
   model: 3com 4510G
+  warranty: 10.2014
   kind: switch
   site: nancy
   snmp_community: public

input/grid5000/sites/nancy/networks/sgraphene4.yaml

 ---
 sgraphene4:
   model: 3com 4510G
+  warranty: 10.2014
   kind: switch
   site: nancy
   snmp_community: public

input/grid5000/sites/nancy/networks/sgravillon1.yaml

 ---
 sgravillon1:
   model: HP Procurve 5406zl J8697A
+  warranty: 03.2012
   kind: switch
   site: nancy
   snmp_community: public

input/grid5000/sites/nancy/networks/sgriffon1.yaml

 ---
 sgriffon1:
   model: 3com 4500g
+  warranty: 03.2012
   kind: switch
   site: nancy
   snmp_community: public

input/grid5000/sites/nancy/networks/stalc2.yaml

 ---
 stalc2:
   model: 3com 4500G
+  warranty: 10.2014
   kind: switch
   site: nancy
   snmp_community: public

input/grid5000/sites/nancy/networks/stalc3.yaml

 ---
 stalc3:
   model: 3com 4500G
+  warranty: 10.2014
   kind: switch
   site: nancy
   snmp_community: public

input/grid5000/sites/nancy/networks/stalc4.yaml

 ---
 stalc4:
   model: 3com 4500G
+  warranty: 10.2014
   kind: switch
   site: nancy
   snmp_community: public