Disable create pool if all disks are offline or parted

Modify free disk filter to check if disk is offline or parted
Fetch disks and pools after a pool is deleted, because disks may now be
free.
Fixes #338

Expose replication framework as a service for better user experience.
Make exception handling in users API consistent
Merge branch 'master' into issue#338_replication_service

Conflicts:
	conf/settings.conf.in
Remove BIN_DIR dependency
Add samba-client as a dependency in buildout
While creating a user, also add the smbpasswd entry.
Merge pull request #331 from sujeetsr/issue#330_create_pool

Disable create pool if all disks are offline or parted
Merge branch 'issue#338_replication_service' of https://github.com/schakrava/rockstor-core into schakrava-issue#338_replication_service

Add warning message on replication page when replication service is not
turned on

Conflicts:
	src/rockstor/storageadmin/views/user.py
Merge pull request #354 from schakrava/issue#338_replication_service

Fixes #338