Resolved: Preservation of para before and after auto spacing.

During import a flag and fixed value is stored in InteropGrabBag and
during export we check for fixed value and value available in para spacing
object. Write autospacing only if para spacing values are not modified during
edit.

Reviewed on:
	https://gerrit.libreoffice.org/6575

Change-Id: If34c5b61c3180b01e68dfe83862784c3d6f33981
DOCX export: fixes for para auto spacing roundtrip

- m_bParaBeforeAutoSpacing / m_bParaBeforeAutoSpacing was never set to false
- m_iParaBeforeSpacing / m_iParaAfterSpacing was uninitialized

Change-Id: I5c8ebd8e4f4c151059916397bc45e0c0ebcf5040