fix file descriptor leaks
Created originally on Bitbucket by benoit-pierre (Benoit Pierre)
Changesets for this Pull Request have not been imported, because it had been already declined on Bitbucket. Marked as closed by the import user.
Unclosed file descriptor in:
- the worksheet read-only code when
ZipFile.openis used without closing the resulting handles - the excel reader code when
ZipFile.readis used with Python<=2.7 for the same reasons