Fixes service only unittest loading
Fixes service only unittest loading

See adb logcat trace after the fix:
```
Android kivy bootstrap done. __name__ is __main__
AND: Ran string
Run user program, change dir and execute entrypoint
Imported unittest
App requirements are:  {'sqlite3', 'python3', 'openssl', 'requests', 'pyjnius', 'libffi'}
Defined test case
Adding Testcase:  tests.test_requirements.Sqlite3TestCase
Adding Testcase:  tests.test_requirements.OpensslTestCase
Adding Testcase:  tests.test_requirements.RequestsTestCase
Adding Testcase:  tests.test_requirements.PyjniusTestCase
Adding Testcase:  tests.test_requirements.LibffiTestCase
Tests to perform are:  {'sqlite3': 'tests.test_requirements.Sqlite3TestCase', 'openssl': 'tests.test_requirements.OpensslTestCase', 'requests': 'tests.test_requirements.RequestsTestCase', 'pyjnius': 'tests.test_requirements.PyjniusTestCase', 'libffi': 'tests.test_requirements.LibffiTestCase'}
..........
----------------------------------------------------------------------
Ran 10 tests in 4.130s

OK
Python for android ended.
```

kivy/python-for-android,rnixx/python-for-android,kivy/python-for-android,kronenpj/python-for-android,PKRoma/python-for-android,germn/python-for-android,kronenpj/python-for-android,PKRoma/python-for-android,kronenpj/python-for-android,PKRoma/python-for-android,kivy/python-for-android,kronenpj/python-for-android,PKRoma/python-for-android,rnixx/python-for-android,germn/python-for-android,kivy/python-for-android,germn/python-for-android,germn/python-for-android,rnixx/python-for-android,kronenpj/python-for-android,rnixx/python-for-android,rnixx/python-for-android,germn/python-for-android,rnixx/python-for-android,germn/python-for-android,kivy/python-for-android,PKRoma/python-for-android