Remove testscenarios denpendency

Since the commit 482e3ce6ab6d21a6349367d8d34d28439adc29c5 had
just removed the NegativeAutoTest Framework, which was the only
user of package testscenarios, testscenarios is no longer used by
tempest. This patch suggests to remove testscenarios from the
package denpendency defined file requirments.txt.

Change-Id: Id2d4ab7c54223044551e4684e9ae1eee130f01c0
1 file changed