Try without identifying current user

Small change that warns the user if the current user cannot be identified rather than aborting.  This came in handy when I put dropbear on a dlink that did not have a true user environment.  Falling back on the "-l" option and user@ options works just fine as a client.  The only implication I found is that the -J option will fail ungracefully without a known own_user.
Test for EAGAIN too
Merge pull request #2 from iquaba/patch-1

Try without identifying current user
merge
Be a bit safer in case pw_name doesn't exist
Don't warn about ENOTSOCK when setting priority
use xauth in /usr/bin

Since the x.org rework, X has been installed into standard paths and not
its own random prefixes.  I think it's time we update the default paths
accordingly.
merge

--HG--
branch : coverity