Fix up build breakage on older compilers in GTMScriptRunner.m

DELTA=21  (11 added, 10 deleted, 0 changed)

git-svn-id: http://google-toolbox-for-mac.googlecode.com/svn/trunk@624 7dc7ac4e-7543-0410-b95c-c1676fc8e2a3
Initial commit
Merge branch 'master' of github.com:pepperpop/google-toolbox-for-mac