bitbake: newbb.vim: fix spelling

(Bitbake rev: 0bd1a3026a26c2c01abd31e265668541f6201bae)

Signed-off-by: Trevor Woerner <trevor.woerner@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/contrib/vim/plugin/newbb.vim

@@ -17,7 +17,7 @@ endif
 fun! <SID>GetUserName()
     let l:user_name = system("git config --get user.name")
     if v:shell_error
-        return "Unknow User"
+        return "Unknown User"
     else
         return substitute(l:user_name, "\n", "", "")
 endfun