Merge pull request #161 from shaitan/master

Removed debug code.
Added `remove_on_fail` error handler

which removes data if checker returned `false`
Removed std::cout debug printing
Uses result_error_handler instead of std::function
Temporarily disable module backend build on rhel6
Merge branch 'master' of github.com:reverbrain/elliptics
Added log output + description of error handler
Disable glob matching for module backend in rpms
Merge pull request #162 from iderikon/master

Added `remove_on_fail` error handler
v2.24.10.5
Introduced elliptics version in the initial handshake. If major versions mismatch (like 2.24 vs 2.23), then connection fails.
Encode server's version in reverse lookup command. Print it if server returned error.
Set need-ack flag if reverse lookup command failed
Merge branch 'master' of github.com:reverbrain/elliptics