Added support in openstack connector for additional disks, either empty or based on an image. Warning! Tested only for v2 Openstack API. Changes for v3 were not implemented

Change-Id: Ice2b39d05620ca3eb90704c07d0c5919e4474793
Signed-off-by: montesmoreno <pablo.montesmoreno@telefonica.com>
diff --git a/vimconn.py b/vimconn.py
index b5f8b07..814be65 100644
--- a/vimconn.py
+++ b/vimconn.py
@@ -303,7 +303,7 @@
         '''
         raise vimconnNotImplemented( "Should have implemented this" )
 
-    def new_vminstance(self,name,description,start,image_id,flavor_id,net_list,cloud_config=None):
+    def new_vminstance(self,name,description,start,image_id,flavor_id,net_list,cloud_config=None,disk_list=None):
         '''Adds a VM instance to VIM
         Params:
             start: indicates if VM must start or boot in pause mode. Ignored