HgWeb: fix uncaught error when url_get() fails
HgWeb: fix uncaught error when url_get() fails

url_get() returns null, not false, so the strict-type check performed
after attempting to retrieve changeset data from HgWeb fails and code
attempts to call commit_changeset() with no data, causing an SQL error.

Removing strict-type check ensures the failed url_get() call is handled
properly.

Fixes #248

make-all/source-integration,mantisbt-plugins/source-integration,mantisbt-plugins/source-integration,make-all/source-integration,dregad/source-integration,mantisbt-plugins/source-integration,make-all/source-integration,dregad/source-integration,dregad/source-integration