[connectionagent] Suppress unnecessary roaming requests.

If a cellular network service is already connected, no ask the user for
confirmation of roaming.
Merge pull request #46 from amccarthy/master

[connectionagent] Suppress unnecessary roaming requests.
Merge pull request #47 from lpotter/master

[connectionagent] fix crash when technology object does not exist
bump version to 0.9.22
[connectionagent] dont allow cell to connect in offline mode.

This helps with too many errors being reported.