[qtcontacts-sqlite] Increase the maximum digits used in minimized phone numbers

Although 7 digits is typically enough to differentiate phone numbers
in their local forms, an eighth digit is sometimes required to
differentiate between a local number and the voicemail service for
that number.
Merge pull request #84 from matthewvogt/max-digits

[qtcontacts-sqlite] Increase the maximum digits used in minimized phone ...