Add integration check to scmlint script.

Check existence for domains and git trees.

Change-Id: I8178c09c7633cf08026ca8f4795c7a9f4d0b2987
Update error message from scmlint.

Block number is hard clue for human to find the error and
parse_blocks() function doesn't returns line number back.

So remove block number information if we can give domain name
or git tree path.

Also remove the errors list from doc string of check.py, since
they are duplicated with doc string in check_domains() and
check_gittrees() function, which is difficult to keep them
always sync.

Change-Id: Icd9e41b6f25f0df86c032df299c5511d3bea61cc
Merge duplicated users from LDAP and import scripts

Add merge feature:
    Keep the LDAP user and merge the roles of user which from import scripts
    into LDAP user.
Do merge when user login.
Run django datamigration to merge the uesrs exist in database.

Fixes: #1921

Change-Id: I7c0ff8a605ad9cf030b9a75348d431b832aaa7bd
Signed-off-by: gaoxuesx <xuesongx.gao@intel.com>