Use shell command to look up CEC_TYPE

Using the native 'env' command in simics causes users to have problems
when reloading checkpoints on pre-axone systems. When you reload
the checkpoint CEC_MODEL is not defined and it gives env an error
which crashes the simics run. Using the shell command allows it
to fail to find the CEC_MODEL variable and is able to continue on.
This is actually reverting back to the original behavior prior
to suggestions from simics team.

Change-Id: Ieefd0d73e0651cf233f94a297f8f4ea2f5f0dbfe
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/72161
Reviewed-by: Hieu C. Nguyen <hieu.nguyen@us.ibm.com>
Reviewed-by: William G. Hoffa <wghoffa@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Reviewed-by: CALEB SCHLOSSIN <calebs@us.ibm.com>
Reviewed-by: Michael J. Walsh <micwalsh@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

src/build/simics/startup.simics

@@ -26,7 +26,7 @@ python "os.environ['HB_TOOLPATH'] = \""+$hb_script_location+"\""
 
 # TODO RTC: 204842 Revist once we get way to read CEC_TYPE from simics
 if ($hb_mode == 1) {
-    $model = (env CEC_TYPE)
+    $model = (shell "printenv CEC_TYPE")
     $machine_name = (shell "printenv MACHINE")
     $hb_machine = "unknown"
     if ($model == "p9_zztop")     {$hb_machine = "zztop"}