Change PhoneNumberUtils MIN_MATCH to match 6 digits.

Argentina and some other Latin American countries
use 6 digits phone numbers. This change extends the
correct number matching digits for these countries.

Change-Id: I3d410c26fb285e5bd5fcd6d235e5ce492b1b2eba
Signed-off-by: David Sobreira <davidps.marques@lge.com>