Fix bug that getBaseBandVersion() may write the value incorrectly.

getBaseBandVersion tries to get value from a legacy API and rewrites it
back. However the read value is the full list but the write is to a
specific phone, causing the list to grow unexpectedly.

Bug: 149342541
Test: manual - using test app, call API and check result.
Change-Id: I78b0443c5e38a30010796fcb69f01a8c7ebaf160