Bug fix for local CI runs

There are three possible runtime enviroments supported by CI scripts:
1. Arm Jenkins
2. OpenCI
3. Local CI

Local CI, in many cases, resembles Arm Jenkins enviroment. This patch
fixes various conditions that effect choice of resources such as paths
of FVP Models etc.

For example, local CI run is picking up the Base_AEM model path as
/opt/model/Base_RevC_AEMv8A_pkg/models/Linux64_GCC-6.4
instead of
/arm/warehouse/SysGen/Models/11.12/38/models/Linux64_GCC-6.4/

Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
Change-Id: Ic1a51ad15868ff9023144ff393e6f964151fcea0
5 files changed