fix #4069 about readonly in TextInput
fix #4069 about readonly in TextInput

matham/kivy,matham/kivy,aron-bordin/kivy,akshayaurora/kivy,kived/kivy,janssen/kivy,jkankiewicz/kivy,kived/kivy,bionoid/kivy,inclement/kivy,autosportlabs/kivy,KeyWeeUsr/kivy,manthansharma/kivy,manthansharma/kivy,jegger/kivy,kivy/kivy,rafalo1333/kivy,akshayaurora/kivy,rnixx/kivy,KeyWeeUsr/kivy,LogicalDash/kivy,andnovar/kivy,autosportlabs/kivy,LogicalDash/kivy,jkankiewicz/kivy,darkopevec/kivy,aron-bordin/kivy,aron-bordin/kivy,rafalo1333/kivy,KeyWeeUsr/kivy,jegger/kivy,kivy/kivy,matham/kivy,rafalo1333/kivy,darkopevec/kivy,jkankiewicz/kivy,andnovar/kivy,inclement/kivy,el-ethan/kivy,Cheaterman/kivy,inclement/kivy,rnixx/kivy,Cheaterman/kivy,LogicalDash/kivy,LogicalDash/kivy,el-ethan/kivy,janssen/kivy,Cheaterman/kivy,jkankiewicz/kivy,rnixx/kivy,el-ethan/kivy,andnovar/kivy,darkopevec/kivy,janssen/kivy,jegger/kivy,bionoid/kivy,tony/kivy,aron-bordin/kivy,manthansharma/kivy,bionoid/kivy,akshayaurora/kivy,tony/kivy,janssen/kivy,Cheaterman/kivy,kived/kivy,kivy/kivy,manthansharma/kivy,jegger/kivy,tony/kivy,KeyWeeUsr/kivy,matham/kivy,autosportlabs/kivy,darkopevec/kivy,bionoid/kivy