xci: Make post merge job common across all scenarios

xci: Make post merge job common across all scenarios

It is difficuly to have post-merge jobs per scenario since we set
the scenario during job runtime and having jobs per scenario makes
things unnecessarily complicated. Apart from that, there is no
reason to have scenario specific merge jobs either since this is
some kind of verify job and everything is same except the scenario
name itself which we extract via set-scenario script.

Daily and further jobs will be scenario specific since they will
be run on timer and we will have ability to specify the scenario.

Change-Id: I3bf6d5ce0fbc48b2d2b2b9695e198bad229ce08d
Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>