mv_machine_learning: clearing up resources in the beginning of each test case

mv_machine_learning: clearing up resources in the beginning of each test case

[Issue type] : bug fix

The RemoveModelResources() function is being called at the end
of the testcases to remove the model files. However, when a
test case fails due to failed assertion, the model files are not
getting removed and this can affect the next testcase.
This patch removes the model files in the beginning as well.

Change-Id: Ib94e894f168c35fe783f6195366369e1b8d18dd5
Signed-off-by: Vibhav Aggarwal <v.aggarwal@samsung.com>