Fix typo. when safemode is enabled we experienced the problem with ini_get arguments number

src/Composer/Util/Git.php

@@ -21,7 +21,7 @@ class Git
 {
     public function cleanEnv()
     {
-        if (ini_get('safe_mode') && false === strpos(ini_get('safe_mode_allowed_env_vars', 'GIT_ASKPASS'))) {
+        if (ini_get('safe_mode') && false === strpos(ini_get('safe_mode_allowed_env_vars'), 'GIT_ASKPASS')) {
             throw new \RuntimeException('safe_mode is enabled and safe_mode_allowed_env_vars does not contain GIT_ASKPASS, can not set env var. You can disable safe_mode with "-dsafe_mode=0" when running composer');
         }