During the sync, syncevolution try to log some information about the event and
crash because the function 'g_variant_new_string' return a null pointer.


The event title contains '"@default/calendar_uoa_5: updating \"Lunch Thursday -
Steph & Joe\377Lunch Thursday w/Steph\""' which is not a valid utf-8 string.
due the '\377'. I am not sure if the char '\377' is part of the event title or
it was generated by a previous conversion. 


This cause this function to crash: (/src/gdbusxx/gdbus-cxx-bridge.h:1510)

g_variant_builder_add_value(&builder, g_variant_new_string(value.c_str());

because the g_variant_new_string returns a null pointer.