VXMICRO_BASE is incorrectly set if vxmicro-env.bash is
sourced from outside the repo root directory
Change-Id: I9aa71bb2f994e5be3e5a0d64086223c54ce2b1a2
Signed-off-by: Todor Minchev <todor.minchev@intel.com>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>