test: cleanup verbosity variant from fatelog test Unlike the '{obsfate}' keyword defined in 'hg-evolve', the definition of hg fatelog in test-obsmarker-template.t is not verbosity dependent. Remove useless call to fatelog -v and fatelog -q.

test: rename obsfate template alias We will introduce an obsfate templatekw in the next patch that will conflict with the obsfate template in the test file, rename the one in test file to avoid this collision.

obsolete: add a devel.user.obsmarker In tests, we often want to use a different username in obs-markers without changing the default user. Add a 'devel.user.obsmarker'.

strip: factor out update target selection The same algorithm was used in two places: one to find out which commit shall become the parent of wdir, and the other to prepare the wdir when keeping changes. Factoring it out prevents inconsistent changes in either occurrence.