fix for basic_20: increases timeout for scaling operation

basic_20 is failing due to the timeout value which is 2 mins.
Thanks to David Aguilar we know that this time should be 4 mins.

Change-Id: I683e486b55dea056fb5e6d041ae7e7bd2c97a0d8
Signed-off-by: aktas <emin.aktas@ulakhaberlesme.com.tr>