[Clas_offline] caldb timeout/reconnect bug

[Nathan Baltzell]

FYI Everyone,

After changes in JLab firewalls on August 16, at least a couple run groups (eg6 and eg4)
started getting new segfaults related to timeout errors in connections to the calibration
database during cooking.  While CLAS already had a mechanism in place to automatically
reconnect in such cases, it had a bug resulting in false success that led to the recent
problems.  

Correctly testing the return value from mysql_ping fixes it, and it’s now in svn’s
trunk/io/caldb/Map/calib_connect.c (line 122), as well as cvs’s 
packages/caldb/Map/calib_connect.c (line 113) just in case.  

The version in svn would probably never have experienced this bug until someone reverts
it back to persistent connections.  But in case anyone else is running older versions
of the code ….

This bug only (?) became relevant after a new 30 minute timeout on dormant connections
implemented in the JLab firewall on 8/16.  Maybe there will be related issues.

Regards,
Nathan