monitor: eliminate monitor_event_state_lock

monitor: eliminate monitor_event_state_lock

This lock does not protect anything that the BQL does not already
protect.  Furthermore, with -nodefaults and no monitor, the mutex
is not initialized but monitor_protocol_event_queue is called
anyway, which causes a crash under mingw (and only works by luck.
under Linux or other POSIX OSes).

Reported-by: Orx Goshen <orx.goshen@intel.com>
Cc: Daniel Berrange <berrange@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
(cherry picked from commit c20b7fa4b2fedd979bcb0cc974bb5d08a10e3448)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>