Item12937: Minor tweak to shebang

Need to keep the Shebang lines consistent with what the rewriteshebang
tool writes.  Otherwise it's painful to switch between perlbrew
installations when running tests across releases.

git-svn-id: http://svn.foswiki.org/trunk/PlainFileStoreContrib@17750 0b4bb1d4-4e5a-0410-9cc4-b2b747904278