catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ic2b49715c7b81ac5bcfc12ff2d3b4c593cd95ce7
diff --git a/user_channel/user_mgmt.cpp b/user_channel/user_mgmt.cpp
index 6ae90fc..b36a2e6 100644
--- a/user_channel/user_mgmt.cpp
+++ b/user_channel/user_mgmt.cpp
@@ -1297,7 +1297,7 @@
                 }
             }
         }
-        catch (Json::out_of_range& e)
+        catch (const Json::out_of_range& e)
         {
             // Key not found in 'userInfo'; possibly an old JSON file. Use
             // default values for all payloads, and SOL payload default is true.