Description of problem:
as summary.

Version-Release number of selected component (if applicable):
v3.8.10-1 on devel server.

How reproducible:
100%

Steps to Reproduce:
1.There is a plan has multiple test version.
2.Invoke TestPlan.filter to filter plan via 'Text' like:
n.TestPlan.filter({'plan_id':10207,'text__in': [20997,20998,20996]})
3.Check the filter result.

Actual results:
system returns only one plan.

Expected results:
system returns three duplicate plan.

Additional info:

In [60]: n.TestPlan.filter({'plan_id':10207,'text__in': [20997,20998,20996]})
Out[60]: 
[{'attachment': [],
  'author': 'qiyang',
  'author_id': 4239,
  'case': [],
  'component': [],
  'create_date': '2014-08-13 18:16:05',
  'env_group': [],
  'extra_link': None,
  'is_active': False,
  'name': 'qiyang test plan a',
  'owner': None,
  'owner_id': None,
  'parent': None,
  'parent_id': None,
  'plan_id': 10207,
  'product': 'qiyang test product',
  'product_id': 343,
  'product_version': 'qiyang-product-version-2',
  'product_version_id': 1479,
  'tag': [],
  'type': 'Unit',
  'type_id': 1},
 {'attachment': [],
  'author': 'qiyang',
  'author_id': 4239,
  'case': [],
  'component': [],
  'create_date': '2014-08-13 18:16:05',
  'env_group': [],
  'extra_link': None,
  'is_active': False,
  'name': 'qiyang test plan a',
  'owner': None,
  'owner_id': None,
  'parent': None,
  'parent_id': None,
  'plan_id': 10207,
  'product': 'qiyang test product',
  'product_id': 343,
  'product_version': 'qiyang-product-version-2',
  'product_version_id': 1479,
  'tag': [],
  'type': 'Unit',
  'type_id': 1},
 {'attachment': [],
  'author': 'qiyang',
  'author_id': 4239,
  'case': [],
  'component': [],
  'create_date': '2014-08-13 18:16:05',
  'env_group': [],
  'extra_link': None,
  'is_active': False,
  'name': 'qiyang test plan a',
  'owner': None,
  'owner_id': None,
  'parent': None,
  'parent_id': None,
  'plan_id': 10207,
  'product': 'qiyang test product',
  'product_id': 343,
  'product_version': 'qiyang-product-version-2',
  'product_version_id': 1479,
  'tag': [],
  'type': 'Unit',
  'type_id': 1}]