Add the "share" and "default" parms to subnet pool create command.
Add the "default" and "no-default" parms to subnet pool set command.
Note that "share" can not be modified once subnet pool has been
created, so do not add this to the set command.
Change-Id: I1eecad69527a1cde7fb234669f4aff2be2db491e
Partial-Bug: #1544591
Partial-Bug: #1544586