PhoneNumberHelper.java: Disable SMS

Part of fixing barrykn/android-cm7-bkndh1#9.
People: Make the search button play dead

Until I figure out how to make the search button disappear altogether,
it will suffice to make it just do nothing.

Part of barrykn/android-cm7-bkndh1#10.
PeopleActivity: Make search button go away forever, for real

I've tested this, so I can now close barrykn/android-cm7-bkndh1#10.