crowbar_join: Try longer to ping the admin server

Apparently, on some hardware, the network card takes 20 seconds to be
up, so just one initial ping is not a good enough test. Let's try for
two minutes.

https://bugzilla.novell.com/show_bug.cgi?id=871460
crowbar_join: Get the hostname before pinging the admin server
crowbar_join: Do not sleep if we're going to fail anyway
Merge pull request #293 from vuntz/admin-server-down

crowbar_join: Try longer to ping the admin server
Try harder in skipping the MSFT compat rules

The by-id/ MS compatibility hack links that were added
as a maintenance update (and thereby are available in
the discovery image) are not recognized by the SP3 install
media, hence missing during install, which breaks.

The previous regexp was not good enough, some harddrives
do not start their naming with a letter, but a number. In
this case it seems udev always prefixes it with "2", so
hopefully this regexp is good enough..

https://bugzilla.novell.com/show_bug.cgi?id=864857
Merge pull request #273 from dirkmueller/release/stoney/master

Try harder in skipping the MSFT compat rules