libpcap: remove explicit dependency for scanner.c

* jam has been updated in btrev43095, which will now
  track multiple generated files from a single action
  correctly
* this also partially undoes the change introduced in
  hrev48061
jam: updated package for btrev43095 [x86_gcc2]
jam: updated package for btrev43095 [x86_64]
jam: updated package for btrev43095 [x86]
UrlTest: cleanup IDN tests.
Use strict mode when url-decoding file requests.

We don't want '+' to become a space here.
Fixes #11109.