[TYPO3-core] RFC: Bug #8260: Update Wizard in install tool force temp-configuration files and load configuration twice

[Steffen Kamper]

Hi olly,

nice you catched this one. Sure, a class shouldn't be in configuration 
files, double read is unnecessary, and clearing cache is needed for update.

+1 by reading and testing, though some tiny remarks

getExtensionCacheBehaviour - this is a bit unlucky as the wording 
doesn't describe what you expect. I would suggest sonething like
"useExtensionCache"

if (!$usePlainValue && defined('TYPO3_enterInstallScript') && 
TYPO3_enterInstallScript) {

There is only one value possible (1), so check for defined is sufficient.

Good you moved the cacheFilePrefix generation in a function!

vg Steffen