APN: add Sprint MVNO Ringplus, Ting update

Added Sprint's MVNO ringplus.  it was added in e1d6d09d
but removed later in e980819a/b28ca702333739b132b51926eff7b2ec6d2fa2fd
for an unknown reason.
Also, Ting (another Sprint MVNO) was updated so that it shows as active when revisting
the "Access Point Names" menu.

Change-Id: I4f8fc540235a8f8ad0df8656de0ffdbde2b83852