There were two issues here:

1) The export filter never exported these keywords.

2) The "flymaincnt" RTF extension we inherited from OOo actually never
worked (i.e. it's like this since 7b0b5cdf, the initial import...), as
RTFVertOrient / RTFHoriOrient's second parameter was stored in 1 bit, so
text::RelOrientation::PAGE_FRAME (7) was read back as 1 instead.

Note that I want to get rid of this flymaincnt extension in the exporter
anyway soon, so killing the RTFVertOrient / RTFHoriOrient duplication is
pointless: the sw version will go away.

Change-Id: I5335567833ecf87e6b0ba7c73150a7b95c57f237