example: make badname demo work with euid=0

example: make badname demo work with euid=0

The stap testsuite may be run under euid=0, so make sure the
test triggers the name filtering.

* sysadmin.examples/general/badname.stp: Drop euid()==0 filtering.
  Use a more specific file name substring, to prevent accidental
  interference with host system during testsuite.
* sysadmin.examples/general/badname.meta: Adjust accordingly.