add possibility to connect two vm on the same bridge.

vm-start.sh

@@ -38,7 +38,7 @@ OPTION available
                             -display gtk -vga qxl
     create_disk=<loc_disk>  Def a create disk to boot on. Is necessary for using create, or need the variable INSTALLATION_DISK_LOCATION to be set.
     net=nat:id                 Add a nat connection to the vm. By default there is already one.
-    net=tap:<tapInterface>   Connect the vm to the tap interface <tapInterface>. Please use the script set-tap.sh as root to create the tap interface. #TODO
+    net=tap:<tapInterface>   Connect the vm to the tap interface <tapInterface>. Please use the script set-tap.sh as root to create the tap interface. in the conf file, a mac field have to be set. for two vm to connect togethers, their mac addresses on the same network have to be differents.
     net=none                The vm will have no network interface
 "
 
@@ -208,7 +208,15 @@ set_net() {
                 -device virtio-net,netdev=${1#*:}"
             ;;
         "tap")
-            echo "tap"
+            echo "ajout de l'interface tap ${1#*:}"
+            if [ "${mac}" == "" ]
+            then
+                echo "error, no mac set"
+                exit 1
+            fi
+            network="${network} \
+                -netdev bridge,id=${1#*:} \
+                -device virtio-net,netdev=${1#*:},mac=${mac}"
             ;;
         "none")
             echo "no interface will be connected."