php71: 7.1.5 -> 7.1.7

Fixes:
* CVE-2017-9224
* CVE-2017-9226
* CVE-2017-9227
* CVE-2017-9228
* CVE-2017-9229

See:
* https://secure.php.net/ChangeLog-7.php#7.1.6
* https://secure.php.net/ChangeLog-7.php#7.1.7

pkgs/development/interpreters/php/default.nix

···
   };
 
   php71 = generic {
-    version = "7.1.5";
-    sha256 = "15w60nrickdi0rlsy5yw6aa1j42m6z2chv90f7fbgn0v9xwa9si8";
+    version = "7.1.7";
+    sha256 = "1y0z5n0kyd15wzmn1lprjgaysbg0z428q9cjbx4dqf3zk296g6q7";
   };
 }