Honor warn-only when purging from local directory.

Fixes issue 2162.
Split up license files, putting each part only where needed.
Removed EXPIRY and LICENSE_COMPANY variables.

Not needed anymore after license checking was removed on nodes.
Improve error messages in dbm_api:DBPathLock
self-diagnostics, create diagnostics directory if not exists
Export DBIdToPath, inject workdir
Add Hichame's DB check to self-diagnostics, persistent state db
Add self-diagnostics DB checks

checksums, classes, observations, file stats, locks, performance
dbm_quick.c needs string_lib.h
Check permission, size for keys in self-diagnostics
Merge pull request #557 from kacfengine/licenseMoving

Split up license files, putting each part only where needed.
Merge pull request #555 from kacfengine/issue-2162

Honor warn-only when purging from local directory.
Merge remote branch 'upstream/master'