fix log message in APIRouter

In _setup_ext_routes(...) and _setup_extensions(...)[0], there are three
logs telling that I'm setuping extensions routes, and these are done,
those failed. At line3 in [0], every resource woulld be logged before
the line 6-7 skip (conintue in Python). So here should be that I'm
'extending' resource, not 'extended'. Similiar in line 38 and line 43,
these two should be what is done and what is failed.

So this patch fix the first log from 'Extended' to 'Entending', and in
third log, 'extending' to 'extended' instend which makes context log
more reasonable.

[0] http://paste.openstack.org/show/60246/

Change-Id: I2de66f1a8e09945e1915b61771a55af6b630369c
Merge "fix log message in APIRouter"