As of now, when a process tries to reacquire a lockfile, we
return EEXIST on Windows and print a different error message.
This means that the unit tests need to look for different error
messages too. Linux uses EDEADLK for the same. EDEADLK feels like
a good error description for Windows too and this also lets us
not change the tests too much. So use it.

Some of the tests in test-lockfile.c uses fork to test a
child's ability to acquire lock. We do not fork in Windows.
We also do not support symlinks on Windows.  So, comment out
those tests.

Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>