CLOUDSTACK-7986 [F5 LB] Failed to execute IPAssocCommand due to com.cloud.utils.exception.ExecutionException: Exception caught in Networking::urn:iControl:Networking/VLAN::create()

added 3 new method to strip partition information from VirtualServer, LBPool, VLAN api response.

With BigIP V11.x VirtualServer, LBPool, VLAN api response has been modified.
Now BigIP returns resource  name with user partition information
ex: if vlanname is vlan-100 then the get_list() will return /Common/vlan-100 (/Common -> Suer portition)
This method will strip the partition information and only returns a list with vlan name (vlan-100)

Signed-off-by: Rajani Karuturi <rajanikaruturi@gmail.com>