assoc.c loop-detection patch

[Miguel DeAvila]

The loop-detection patch assoc.c prints a message in the assoc_find() function indicating
that a loop was discovered and the state of the 'expanding' variable. 

If it's of any help, the 'expanding' variable is false in the core dumps I've captured.

We still get the loop problem intermittently. I'd be happy to add more diagnostics, but would need
some guidance about what to add.

thanks,

Miguel