catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: If6aba71f482f75143e6d669763b8853db22318cf
diff --git a/utility.cpp b/utility.cpp
index ee65cff..04cb6ae 100644
--- a/utility.cpp
+++ b/utility.cpp
@@ -168,7 +168,7 @@
         getProperty<int32_t>(POWER_IFACE, "state", POWER_OBJ_PATH, service, bus,
                              state);
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
         log<level::INFO>("Failed to get power state.");
     }