catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: If8dcf70005aebd4ca633b91d6f96badf4a5cd326
diff --git a/policy_find.cpp b/policy_find.cpp
index 191240e..bf58301 100644
--- a/policy_find.cpp
+++ b/policy_find.cpp
@@ -284,7 +284,7 @@
                 return value;
             }
         }
-        catch (std::exception& e)
+        catch (const std::exception& e)
         {
             using namespace phosphor::logging;
             log<level::ERR>("Invalid PROCEDURE value found",