Use the right path for the suggested PHP invocation in ext_skel.

Fixes bug #67160 (ext_skel outputs incorrect information).
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  Use the right path for the suggested PHP invocation in ext_skel.
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Use the right path for the suggested PHP invocation in ext_skel.