Fix chrome host webrequest permissions

[nuriofernandez]

Unchecked runtime.lastError: You need to request host permissions in the manifest file in order to be notified about requests from the webRequest API.

https://developer.chrome.com/extensions/webRequest
https://developer.chrome.com/apps/permissions

Investigate about:
optional_permissions
chrome.permissions.contains
chrome.permissions.request

[nuriofernandez]

Seems to be that optional permissions can not be used the way I expected. Maybe it's necessary to put all domain permissions back to the normal manifest's permissions.