Comment 4 for bug 1312263

I double checked other OS and all of them allow to save a number without a name.
Reasons:
1. You don't want to associate a name because you will recognise the number without the name (there are ppl who store their PIN codes in their contacts) or you are in a hurry and will edit it later.
2. In some cases contacts synced with other services don't have names but only numbers and/or email addresses.
Thus we should allow saving numbers without associated names.