Plug leaks with allocated regular expressions

Sponsored-by: EMC / Isilon Storage Divison
Remove an unused variable
Merge branch 'master' into plug-leaks-with-regex-handling
Copy original_preg and fix a double-free

- Make a copy of original_preg so the regular expression object is valid
when the error is constructed [*].
- Fix a double-free with preg in kyua_tap_try_parse_plan(..) (I fixed this
before on a different branch..).

[*] Submitted-by: jmmv
Sponsored-by: EMC / Isilon Storage Division
Merge pull request #96 from yaneurabeya/plug-leaks-with-regex-handling

Plug leaks with regex handling