Auxiliary::Web::Path.from_model: inputs => form.inputs

Fixed uninitialized variable error.
Merge remote-tracking branch 'tasos-r7/bug/web-fuzzable-path' into rapid7

[Closes #1578]
Auxiliary::Web#log_*: details[:category] => #name

Recent category updates to modules caused variations of vulns of the
same type to be ignored leading to a smaller exploitation surface.
Thus, use the #name of the module as the key instead of the category name.