logger: Apply default console logging when configuration cannot be loaded.

When logger.conf is missing or invalid enable console logging and display
an error message.

ASTERISK-24817 #close
Reported by: Corey Farrell
Review: https://reviewboard.asterisk.org/r/4497/
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Merged revisions 433122 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 433126 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@433130 65c4cc65-6c06-0410-ace0-fbb531ad65f3