ecore: avoid breaking next main loop start if quit occurs outside of loop

ecore: avoid breaking next main loop start if quit occurs outside of loop

in the case where ecore_main_loop_quit() was called before ecore_main_loop_begin(),
the latter call would exit immediately without ever iterating the main loop

@fix

Reviewed-by: Cedric BAIL <cedric.bail@free.fr>
Differential Revision: https://phab.enlightenment.org/D9360