log error conditions more consistently

[Galen Charlton]

Following up on my comment in bug 877430, it would be useful to have various error conditions logged consistently regardless of the language that the service is written in. As a specific example, Perl services now produce a warning if an outgoing message is larger than a configured threshold:

[2011-10-18 09:48:37] opensrf.settings [WARN:3354:Client.pm:117:] Sending large message of 17577 bytes to <email address hidden>/settings_grabber_app1.mig.esilibrary.com_1318945717.320986_3389

Whereas C services pass along a direct error message from ejabberd:

osrfwarn.log:2011-10-17 21:44:08 foobarbaz open-ils.cstore: [WARN:14225:transport_session.c:870:131891220327364498] Text of error message received from Jabber: XML stanza is too big