[oe] Reference to sysroot in PHP packages

[Ash Charles]

It looks like this is fixed by this patch [1].

<snip>
commit 18a97c00b77bfc5eff2214f81934e0dd4d4954b9
Author: Paul Eggleton <paul.eggleton at linux.intel.com>
Date:   Wed Dec 31 15:26:44 2014 +0000

    php: integrate modphp
<snip>

[1] http://permalink.gmane.org/gmane.comp.handhelds.openembedded/67115