cdr_adaptive_odbc: Also apply a filter when the CDR value is empty.

cdr_adaptive_odbc: Also apply a filter when the CDR value is empty.

Extra CDR records are written if a filtered CDR value is empty because the
filter is not checked.

(closes issue ASTERISK-22272)
Reported by: Jordi Llull Chavarria
........

Merged revisions 401577 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 401579 from http://svn.asterisk.org/svn/asterisk/branches/11
........

Merged revisions 401581 from http://svn.asterisk.org/svn/asterisk/branches/12

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@401582 65c4cc65-6c06-0410-ace0-fbb531ad65f3