Make WikiPage::$mPreparedEdit public

Partial revert of I2c34baaf8b64b204444efa1bfa6ea356e0124c54

Bug: 60054

Change-Id: Id4e90c612941ff2bdb50d7a68f4e18b004c9f744
(cherry picked from commit 09f84556bd33d2eeca29cf0d01b641030f50fb8a)
Check for very old PCRE versions in installer and updater

RE_IPV6_ADD uses (?(-n)) ("relative reference condition"), and CSSMin uses
\K ("reset start of match"), which only work in PCRE 7.2 and later -- newer
versions than the PCRE 6.6 included with Red Hat Enterprise Linux 5 and its
derivatives (e.g. CentOS 5).

Because the WMF developers, in general, do not seem to support maintaining
compatibility with such old software versions, I have opted to add a check
to the MediaWiki installer for these versions of PCRE. Affected users are
directed to a MediaWiki.org page advising the use of a different PHP package
that uses the bundled PCRE version instead of the older system version.

For now, the minimum PCRE version is set to 7.2, the oldest version not
known to break MediaWiki core. Once PHP 5.3 support is dropped, we may be
able to require PCRE 8.12 (bundled with PHP 5.4.0) or later.

The existing check for mere existence of the PCRE functions is removed;
since PHP 5.3, it is impossible to compile PHP without PCRE support.

Bug: 58213
Change-Id: Icf3732b6f84eeb25990178ae8fe3bd0fe4cc833f
(cherry picked from commit b215d91224f711e263126ae3b8546e022f33ef00)
SECURITY: Sanitize shell command args

Add validation and sanitization to several code paths.


Bug: 60339
Change-Id: Id124281d21ec730a2e0bbace843dd97194a712b4
Update Release Notes and Version number

Change-Id: If71074f25a73c6c078a11b9ef453c27d0125ab42
Merge tag 'tags/1.22.2' into master-accs

Security Release 1.22.2
Reorganized clients pecific variables (all configs which need adjustments
are in one place now)