[Tails-dev] Quick search not working in Synaptic

As reported through Whisperback, the "Quick search" feature of the main
window of Synaptic is disabled in Tails. Still the "Search" feature
works as expected.

This is surely due to the fact that apt-xapian-index is not installed in
Tails. So, first of all, do we care about that enough to install it by
default?

Second, I tried to install it and it's not usable out-of-the-box. The
command `update-apt-xapian-index` crashed with the following error message:

xapian.DatabaseLockError: Unable to get write lock on
/var/cache/apt-xapian/index/index.4: Cannot allocate memory

Shall I create a ticket for that or just drop the ball?