ovsdb-server.at: Adjust PKIDIR for ssl test.

ovsdb-server.at: Adjust PKIDIR for ssl test.

For this particular test, we pass the PKIDIR through a
ovsdb-tool transact and msys does not convert the path style.
(On Windows, we have to pass the directory in the form C:/foo/bar.pem.)

So get the Windows style path through 'pwd -W'(which is called through
the function pwd ())

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