catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: If6aba71f482f75143e6d669763b8853db22318cf
diff --git a/phosphor-regulators/src/interfaces/manager_interface.cpp b/phosphor-regulators/src/interfaces/manager_interface.cpp
index 47c233d..9e1cb34 100644
--- a/phosphor-regulators/src/interfaces/manager_interface.cpp
+++ b/phosphor-regulators/src/interfaces/manager_interface.cpp
@@ -53,7 +53,7 @@
 
             reply.method_return();
         }
-        catch (sdbusplus::exception_t& e)
+        catch (const sdbusplus::exception_t& e)
         {
             return sd_bus_error_set(error, e.name(), e.description());
         }
@@ -88,7 +88,7 @@
 
             reply.method_return();
         }
-        catch (sdbusplus::exception_t& e)
+        catch (const sdbusplus::exception_t& e)
         {
             return sd_bus_error_set(error, e.name(), e.description());
         }