catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Iee4354d96981eac216425c71668f8eb72e146977
diff --git a/snmp_conf_manager.cpp b/snmp_conf_manager.cpp
index f7edfe0..73e2544 100644
--- a/snmp_conf_manager.cpp
+++ b/snmp_conf_manager.cpp
@@ -41,7 +41,7 @@
         // just to check whether given address is valid or not.
         resolveAddress(address);
     }
-    catch (InternalFailure& e)
+    catch (const InternalFailure& e)
     {
         log<level::ERR>("Not a valid address"),
             entry("ADDRESS=%s", address.c_str());