tests: adjust to look for network-bind-plug

[zyga]

With snapcore/core#32 merged we need to adjust master to let tests pass again. They are using the edge core snap and that has just been built with network-bind-plug.

Signed-off-by: Zygmunt Krynicki zygmunt.krynicki@canonical.com

[zyga]

A lot more network errors than usually.

error: cannot find snap "pi2": Get https://search.apps.ubuntu.com/api/v1/snaps/details/pi2?channel=edge&fields=anon_download_url%2Carchitecture%2Cchannel%2Cdownload_sha3_384%2Csummary%2Cdescription%2Cdeltas%2Cbinary_filesize%2Cdownload_url%2Cepoch%2Cicon_url%2Clast_updated%2Cpackage_name%2Cprices%2Cpublisher%2Cratings_average%2Crevision%2Cscreenshot_urls%2Csnap_id%2Csupport_url%2Ccontact%2Ctitle%2Ccontent%2Cversion%2Corigin%2Cdeveloper_id%2Cprivate%2Cconfinement: net/http: request canceled (Client.Timeout exceeded while awaiting headers)