[TECHNICAL SUPPORT] LPS-34437 Fixed DuplicateFileExecption during import

Hi Sergio,

Based on our conversation I resend https://github.com/sergiogonzalez/liferay-portal/pull/783 in this PR as the blocking issue: http://issues.liferay.com/browse/LPS-35073 is no longer reproducible.

Regards,
Vilmos