Remove volume source option on some dialogs

When creating a volume from snapshot or image, volume source
option should not be displayed.

Change-Id: I27d1a8e23b3ccf6c57922309bddf28dc9a76bab7
Closes-Bug: #1282845
Live Migration should not contain current host in the new host list

Change-Id: I30af5aa4943284edc16dfbde1b1354951698c77c
Closes-Bug: #1267733
Merge "Live Migration should not contain current host in the new host list"
Merge "Remove volume source option on some dialogs"