catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ic8e6ade739bd5ea6e79cac6b9bb2b182748e10c8
diff --git a/extensions/openpower-pels/pel.cpp b/extensions/openpower-pels/pel.cpp
index a6e4d3d..891436d 100644
--- a/extensions/openpower-pels/pel.cpp
+++ b/extensions/openpower-pels/pel.cpp
@@ -619,7 +619,7 @@
             }
         }
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
     }