Remove non-existent contacts from roster without throwing an error.
Remove non-existent contacts from roster without throwing an error.

Zauberstuhl/vines,Zauberstuhl/vines,diaspora/vines,Zauberstuhl/diaspora-vines,negativecode/vines,negativecode/vines,diaspora/vines,Zauberstuhl/diaspora-vines,AliEn707/vines,artofhuman/vines,AliEn707/vines,artofhuman/vines,AliEn707/vines,artofhuman/vines