Previously, RedirectMatch rules were evaluated using Python's re regexp
module. However, Apache httpd uses the PCRE library for evaluating
regular expressions,[1] and there are subtle differences between the
Python and PCRE implementations. Using the PCRE library itself (via the
pcre-python binding) provides more representative results, and hence
more confidence to the user that any rules that pass whereto's tests
will work in the same way in a real Apache configuration.
[1] https://httpd.apache.org/docs/trunk/glossary.html#regex
Change-Id: Ibef3376d9da0688d0c97f5837dacc5b7cc52431c
797cb67a37