Add koji_tag into resolved buildrequires

This is useful for an issue I'm working on, for which I need to get
platform module's koji_tag.

Signed-off-by: Chenxiong Qi <cqi@redhat.com>

module_build_service/resolver/DBResolver.py

@@ -200,7 +200,8 @@ class DBResolver(GenericResolver):
                         'ref': None,
                         'stream': local_build.stream,
                         'version': local_build.version,
-                        'context': local_build.context
+                        'context': local_build.context,
+                        'koji_tag': local_build.koji_tag,
                     }
                     continue
 
@@ -233,7 +234,8 @@ class DBResolver(GenericResolver):
                     'ref': commit_hash,
                     'stream': module_stream,
                     'version': build.version,
-                    'context': build.context
+                    'context': build.context,
+                    'koji_tag': build.koji_tag,
                 }
 
         return new_requires

module_build_service/resolver/MBSResolver.py

@@ -309,6 +309,7 @@ class MBSResolver(GenericResolver):
                     'stream': local_build.stream,
                     'version': local_build.version,
                     'context': local_build.context,
+                    'koji_tag': local_build.koji_tag,
                     # No need to set filtered_rpms for local builds, because MBS
                     # filters the RPMs automatically when the module build is
                     # done.
@@ -350,6 +351,7 @@ class MBSResolver(GenericResolver):
                     'stream': module_stream,
                     'version': str(version),
                     'context': module["context"],
+                    'koji_tag': module['koji_tag'],
                     'filtered_rpms': filtered_rpms,
                 }
             else:

tests/test_resolver/test_db.py

@@ -129,7 +129,9 @@ class TestDBModule:
         assert result == {
             'testmodule': {
                 'stream': 'master', 'version': '20170109091357', 'context': u'78e4a6fd',
-                'ref': 'ff1ea79fc952143efeed1851aa0aa006559239ba'}}
+                'ref': 'ff1ea79fc952143efeed1851aa0aa006559239ba',
+                'koji_tag': 'module-testmodule-master-20170109091357-78e4a6fd'
+            }}
 
     def test_resolve_profiles(self):
         """