fixed some syntax issues (string formatting) with migration files

rhodecode/lib/dbmigrate/schema/db_1_4_0.py

@@ -787,7 +787,7 b' class Repository(Base, BaseModel):'
         from rhodecode.lib.vcs.backends.git import GitRepository
         required = (MercurialRepository, GitRepository)
         if not isinstance(repo, required):
-            raise Exception('repo must be instance of %s' % required)
+            raise Exception('repo must be instance of %s' % (','.join(required)))
 
         # inject ui extra param to log this action via push logger
         for k, v in extras.items():

rhodecode/lib/dbmigrate/schema/db_1_5_0.py

@@ -807,7 +807,7 b' class Repository(Base, BaseModel):'
         from rhodecode.lib.vcs.backends.git import GitRepository
         required = (MercurialRepository, GitRepository)
         if not isinstance(repo, required):
-            raise Exception('repo must be instance of %s' % required)
+            raise Exception('repo must be instance of %s' % (','.join(required)))
 
         # inject ui extra param to log this action via push logger
         for k, v in extras.items():

rhodecode/lib/dbmigrate/schema/db_1_5_2.py

@@ -873,7 +873,7 b' class Repository(Base, BaseModel):'
         from rhodecode.lib.vcs.backends.git import GitRepository
         required = (MercurialRepository, GitRepository)
         if not isinstance(repo, required):
-            raise Exception('repo must be instance of %s' % required)
+            raise Exception('repo must be instance of %s' % (','.join(required)))
 
         # inject ui extra param to log this action via push logger
         for k, v in extras.items():