Create Xapian::WritableDatabase with DB_NO_TERMLIST Flag

[maneeshpm]

Fixes #417

We do not use any operation that requires the use of a xapian term list. Removing it makes our indexes a bit leaner. Refer discussion on the linked issue for more info.

Changes included in this PR:

• Use Xapian::DB_NO_TERMLIST flag along with Xapian::DB_CREATE_OR_OVERWRITE to create xapian database

[codecov]

Codecov Report

Merging #528 (a1c9d96) into master (d4801b6) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #528   +/-   ##
=======================================
  Coverage   76.36%   76.36%           
=======================================
  Files          89       89           
  Lines        3655     3655           
  Branches     1640     1625   -15     
=======================================
  Hits         2791     2791           
  Misses        863      863           
  Partials        1        1           

Impacted Files	Coverage Δ
src/writer/xapianIndexer.cpp	96.42% <100.00%> (ø)

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[kelson42]

Why not using directly xapian::DB_CREATE_OR_OVERWRITE | xapian::DB_NO_TERMLIST?

[maneeshpm]

@kelson42 I wanted to make the hierarchy clear. Xapian::DB_CREATE_OR_OVERWRITE is the default flag, we are attaching an additional feature flag Xapian::DB_NO_TERMLIST onto it. But yes, it's just a matter of preference. Do you think we should have it directly?

[kelson42]

Yes