Used default values of PSEUDO_* environment variables only
if variables are not set.
This allows to set custom PSEUDO_PREFIX and other pseudo
variables in order to use pseudo database from non-standard
locations.
Change-Id: I0bc1af5e521121d1f96d590cb6edb23cf0cb0b83 Signed-off-by: Ed Bartosh <eduard.bartosh@intel.com> Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>