Don't mix str and unicode types when dealing with passwords, set everything to str.
Don't mix str and unicode types when dealing with passwords, set everything to str.

fix #386

RavenB/modoboa,mehulsbhatt/modoboa,bearstech/modoboa,tonioo/modoboa,modoboa/modoboa,tonioo/modoboa,RavenB/modoboa,carragom/modoboa,carragom/modoboa,carragom/modoboa,modoboa/modoboa,mehulsbhatt/modoboa,tonioo/modoboa,modoboa/modoboa,modoboa/modoboa,bearstech/modoboa,RavenB/modoboa,bearstech/modoboa,mehulsbhatt/modoboa,bearstech/modoboa