Fix occ-control terminations

1. Ensure PowerMode object created before attempting to use
2. Only call setChassisAssociation after getting successful temperature
reading.

Tested on Everest hw

Change-Id: I308c072cf5ab0235086c136ba7644125de0a8c6a
Signed-off-by: Chris Cain <cjcain@us.ibm.com>
diff --git a/occ_pass_through.cpp b/occ_pass_through.cpp
index 6cf6374..ea640ef 100644
--- a/occ_pass_through.cpp
+++ b/occ_pass_through.cpp
@@ -137,6 +137,12 @@
         return false;
     }
 
+    if (!pmode)
+    {
+        log<level::ERR>("PassThrough::setMode: PowerMode is not defined!");
+        return false;
+    }
+
     log<level::INFO>(
         fmt::format("PassThrough::setMode() Setting Power Mode {} (data: {})",
                     newMode, modeData)