catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I2afb405177268451e44f0aff8417777a00d292d9
diff --git a/host_state_manager.cpp b/host_state_manager.cpp
index 16f2bbf..8d35a07 100644
--- a/host_state_manager.cpp
+++ b/host_state_manager.cpp
@@ -364,7 +364,7 @@
         }
         return false;
     }
-    catch (cereal::Exception& e)
+    catch (const cereal::Exception& e)
     {
         error("deserialize exception: {ERROR}", "ERROR", e);
         fs::remove(path);