app migrate: Use = instead of LIKE as described in the comment above.

The LIKE operator is not defined on integers (probably any non-text) columns
on PostgreSQL.
make log date configurable, default to iso 8601
add reveal mimetype
Port log level filtering from OC_Log_Owncloud to OC_Log_Syslog.
[tx-robot] updated from transifex
fixing PHPDoc
add 'logdateformat' to config.sample.php
fixing PHPDoc
Merge pull request #4228 from owncloud/fix-3836

app migrate: Use = instead of LIKE as described in the comment above.
Merge pull request #4308 from owncloud/fix-4194

Port log level filtering from OC_Log_Owncloud to OC_Log_Syslog.
Merge pull request #4293 from owncloud/config-date

make log date configurable, default to iso 8601