fix calling of notifications. remove deadlock in 'eom_set_output_attribute'

fix calling of notifications. remove deadlock in 'eom_set_output_attribute'

Cause of deadlock:
'eom_set_output_attribute' locks eom_mutex, then it calls eom wayland implementation 'eom_wayland_client_set_attribute' function. It sets attribute and waits for Enlightenment reply by invocation of 'wl_display_dispatch' and 'wl_display_roundtrip'. When client handles '_eom_wl_eom_output_attribute' it calls 'eom_wl_output->client_info->func' in the end, the func is '_eom_output_process_notify_cb'. '_eom_output_process_notify_cb' func is try to lock eom_mutex which is already locked by 'eom_set_output_attribute'.

Change-Id: I6bea2b765d2636e8766a8dd3077c6081e0cae5dd
Signed-off-by: Roman Peresipkyn <r.peresipkyn@samsung.com>