fixes regressions from a2612ef2a43488c4c71632c56a240b8f022f1c09
for example:

"FileAlreadyExistsException: license.html" in
org.eclipse.pde.build.internal.tests.p2.PublishingTests.testBug266488()

"p2.inf doesn't exist" in
org.eclipse.pde.build.internal.tests.p2.PublishingTests.testBug271373()