ceph: make use of "else" where appropriate

Rearrange ceph_tcp_connect() a bit, making use of "else" rather than
re-testing a value with consecutive "if" statements.  Don't record a
connection's socket pointer unless the connect operation is
successful.

Signed-off-by: Alex Elder <elder@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>