serialize: Replace cereal::RapidJSONException with cereal::Exception

cereal::RapidJSONException is inherited from cereal::Exception.
Currently if the code hits a cereal::Exception, the exception is not
caught and the BMC updater service fails to start. Change it to
catch cereal::Exception, which would also catch cereal::RapidJSONException.

Tested: Caused both kinds of exceptions and verified they were caught.
        Printing the e.what():
        - cereal::Exception - Request non-existent name:
          Nov 04 19:52:22 witherspoon-128-Y330UF73C00D phosphor-image-updater[630]: JSON Parsing failed - provided NVP (purpose) not found
        - cereal::RapidJSONException - Corrupted json:
          Nov 04 19:52:23 witherspoon-128-Y330UF73C00D phosphor-image-updater[630]: rapidjson internal assertion failure: IsObject()

Change-Id: I62a7f4ebf07c4f53db0f77819e43bed773ec9969
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/serialize.cpp b/serialize.cpp
index 2acc373..b61233c 100644
--- a/serialize.cpp
+++ b/serialize.cpp
@@ -41,7 +41,7 @@
             iarchive(cereal::make_nvp("priority", priority));
             return true;
         }
-        catch (cereal::RapidJSONException& e)
+        catch (cereal::Exception& e)
         {
             fs::remove(path);
         }