Using the syncer as configured by `configuresmoke.pl`

When running smokecurrent.sh, the default syncer (at present 'git', as
returned by the `syncer()` method in `Test::Smoke::App:Options`) is used instead
of that configured by using `configuresmoke.pl`.  This change implements a
hack (i.e. I'm not 100% sure this is the right place to put this change,
however can't find the appropriate place to update the 'syncer'
configuration value).  The fundamental problem is that the 'sync_type'
option (set in the `_final_options` part of the entire configuration) doesn't
override the default 'syncer' option.  Interestingly enough, the 'sync_type'
option is used when instantiating the `Test::Smoke::Syncer` object in
`tssynctree.pl`.  This change thus makes the behaviour of both `tssmokeperl.pl`
and `tssynctree.pl` consistent.