Update readme.txt

PHP version was backwards.
Merge pull request #2702 from bitclaw/patch-1

Update readme.txt
Revert "Merge pull request #2702 from bitclaw/patch-1"

This reverts commit ee57245edecd6c2e7c2cd48a74ccd806b29b3a7c, reversing
changes made to 1466f7d70a6f3baa441fbc1058a0180e4d0dfd7c.