[IMAPx] Stop IDLE gracefully
[IMAPx] Stop IDLE gracefully

My previous changes caused IDLE not to be stopped gracefully, which
could cause several issues and side effects, for example if ever seen
an error "Stream has outstanding operation" in UI, then it was one
of the issues being caused by it.

tintou/evolution-data-server,matzipan/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,tintou/evolution-data-server