Fix gittree attribute error when get packages

Change-Id: Ia44127fbbce5a3f676e6468dbab2165456602f03
Fixes: #2032
Use requests instead of urllib2

Requests allow you to send HTTP/1.1 requests. You can add headers, form data,
multipart files, and parameters with simple Python dictionaries, and access the
response data in the same way. It's powered by httplib and urllib3, it is much
more simpler and cleaner.
Urllib2 requires an enormous amount of work to perform the simplest of tasks.

Change-Id: Ibdacaebb9c450a8343a6ad5f48c2b210469bce5c
Signed-off-by: gaoxuesx <xuesongx.gao@intel.com>
Image data migration

The Image name in IRIS DB has space, so strip space in the Image name.
Fixes: #2029

Change-Id: I425e10aaad963159f1cbdfeee54beb3d2c98db05
Signed-off-by: gaoxuesx <xuesongx.gao@intel.com>
Set fields name, target, product unique_together

The fields name, target, product should be unique, and unique field type
must be CharField.

Change-Id: I422ecc001942a10b0c6eb7ade2c608ac83981e4f
Signed-off-by: gaoxuesx <xuesongx.gao@intel.com>
Fixes the remove feature of entity and relation

The script removes other Images which don't belong to one Product.
It also removes the relationship between products and trees, and between
trees and packages of one Product, the relationship maybe exist in
the other Product.

Change-Id: I271de9db80910a4cc56c5295e6ed3a70788d061a
Signed-off-by: gaoxuesx <xuesongx.gao@intel.com>