MDL-36196 hardcode the required PHP version in installer

install.php

@@ -56,10 +56,8 @@
 @error_reporting(E_ALL);
 @ini_set('display_errors', '1');
 
-// Check that PHP is of a sufficient version
-// PHP 5.2.0 is intentionally checked here even though a higher version is required by the environment
-// check. This is not a typo - see MDL-18112
-if (version_compare(phpversion(), "5.2.0") < 0) {
+// Check that PHP is of a sufficient version.
+if (version_compare(phpversion(), '5.3.2') < 0) {
     $phpversion = phpversion();
     // do NOT localise - lang strings would not work here and we CAN not move it after installib
     echo "Moodle 2.1 or later requires at least PHP 5.3.2 (currently using version $phpversion).<br />";