Don't need to init testr explicitly

In run_tests.sh, function init_testr will initialize testr if the
directory .testrepository is not existed. Actually, testr will do
the check before run the test:

In Python package testrepository, setuptools_command.py:Testr.run

68 def run(self):
69 """Set up testr repo, then run testr"""
70     if not os.path.isdir(".testrepository"):
71         self._run_testr("init")

"python setup.py testr" will trigger this function to create
.testrepository if not exist.

So, init_testr can be removed safely.

Fixes Bug #1220149

Change-Id: I4dfcdfa5e1e323bbc7ee3add5d9d0888a42e3812
Merge "Don't need to init testr explicitly"