Add support for SINCEDB_DIR to file input
Add support for SINCEDB_DIR to file input

This change allows you to change the destination of sincedb files without having to change the $HOME environment variable.  If set, SINCEDBB_DIR will override HOME as the destination of default sincedb files.
opentable/logstash-kafka,tinglinux/logstash-kafka,opentable/logstash-kafka,joekiller/logstash-kafka,Aloomaio/logstash-kafka,joekiller/logstash-kafka,Aloomaio/logstash-kafka,tinglinux/logstash-kafka