exec: Don't assume request presence when logging

Use DEBUG* macros for logging, instead of RDEBUG* macros in
radius_start_program and radius_readfrom_program as these are not
guaranteed to be invoked with a valid request.

For example, not from most of the exec_trigger invocations.
raddb: Remove extra apostrophe from trigger.conf

Remove a spurious apostrophe from trigger.conf's trigger.modules.args.

This fixes module triggers, otherwise producing this error:

    rad_expand_xlat: Invalid string passed as argument
raddb: Use appropriate module names in traps

Specify appropriate module names for all module traps in trigger.conf,
instead of using "ldap" for all.
Merge pull request #811 from spbnick/trigger_fixes

Trigger fixes