catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ia4086e77ad205e9a6a73a6ca570036818e3069fe
diff --git a/src/storagecommands.cpp b/src/storagecommands.cpp
index e7ee3ad..6586fff 100644
--- a/src/storagecommands.cpp
+++ b/src/storagecommands.cpp
@@ -106,7 +106,7 @@
             auto reply = dbus.call(managedObj);
             reply.read(managedObjects);
         }
-        catch (sdbusplus::exception_t&)
+        catch (const sdbusplus::exception_t&)
         {
             phosphor::logging::log<phosphor::logging::level::ERR>(
                 "Error getting managed objects from connection",
@@ -142,7 +142,7 @@
     {
         sdbusplus::message::message writeFruResp = dbus.call(writeFru);
     }
-    catch (sdbusplus::exception_t&)
+    catch (const sdbusplus::exception_t&)
     {
         // todo: log sel?
         phosphor::logging::log<phosphor::logging::level::ERR>(
@@ -185,7 +185,7 @@
         sdbusplus::message::message resp = dbus.call(getObjects);
         resp.read(frus);
     }
-    catch (sdbusplus::exception_t&)
+    catch (const sdbusplus::exception_t&)
     {
         phosphor::logging::log<phosphor::logging::level::ERR>(
             "replaceCacheFru: error getting managed objects");
@@ -269,7 +269,7 @@
         sdbusplus::message::message getRawResp = dbus.call(getRawFru);
         getRawResp.read(fruCache);
     }
-    catch (sdbusplus::exception_t&)
+    catch (const sdbusplus::exception_t&)
     {
         lastDevId = 0xFF;
         cacheBus = 0xFF;
@@ -456,7 +456,7 @@
         sdbusplus::message::message resp = dbus.call(getObjects);
         resp.read(frus);
     }
-    catch (sdbusplus::exception_t&)
+    catch (const sdbusplus::exception_t&)
     {
         return IPMI_CC_RESPONSE_ERROR;
     }