catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ic8e6ade739bd5ea6e79cac6b9bb2b182748e10c8
diff --git a/extensions/openpower-pels/user_data_json.cpp b/extensions/openpower-pels/user_data_json.cpp
index 9d331a3..107e026 100644
--- a/extensions/openpower-pels/user_data_json.cpp
+++ b/extensions/openpower-pels/user_data_json.cpp
@@ -344,7 +344,7 @@
                         return prettyJSON(componentID, subType, version, json);
                     }
                 }
-                catch (std::exception& e)
+                catch (const std::exception& e)
                 {
                     log<level::ERR>("Bad JSON from parser",
                                     entry("ERROR=%s", e.what()),
@@ -414,7 +414,7 @@
                                  creatorID);
         }
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
         log<level::ERR>("Failed parsing UserData", entry("ERROR=%s", e.what()),
                         entry("COMP_ID=0x%X", componentID),