Fix a problem in resolving the `url` key of a created event
Fix a problem in resolving the `url` key of a created event

The `url` parameter of handle_data() could hold a string or nil when
invoked from handle_event_data(), in which case resolving `url` in a
created event would fail with a type error.  Moreover, the logic did not
have any guard for URI errors.  This commit should fix them.

Fixes #1765.

CodeHunter2006/huginn,johnleeming/huginn,jezcope/huginn,Ishfal/huginn,johnleeming/huginn,breandan/huginn,eugenesvk/huginn,gautamkrishnar/huginn,cantino/huginn,Ishfal/huginn,djolivier/huginn,johnleeming/huginn,eugenesvk/huginn,strugee/huginn,Ishfal/huginn,dsander/huginn,eugenesvk/huginn,albertsun/huginn,gautamkrishnar/huginn,brianpetro/huginn,mathias/huginn,virtadpt/huginn,megaxox/huginn,albertsun/huginn,mathias/huginn,cantino/huginn,megaxox/huginn,strugee/huginn,omniscopeio/huginn,albertsun/huginn,naiyt/huginn,huginn/huginn,dsander/huginn,CodeHunter2006/huginn,cantino/huginn,omniscopeio/huginn,younata/huginn,djolivier/huginn,megaxox/huginn,breandan/huginn,jezcope/huginn,mathias/huginn,brianpetro/huginn,younata/huginn,breandan/huginn,strugee/huginn,huginn/huginn,naiyt/huginn,brianpetro/huginn,virtadpt/huginn,naiyt/huginn,djolivier/huginn,virtadpt/huginn,jezcope/huginn,dsander/huginn,gautamkrishnar/huginn,younata/huginn,huginn/huginn,omniscopeio/huginn,CodeHunter2006/huginn