Ergh!  Don't mix `%doc <relativepathname>' with `%doc <absolutepathname>'
where <absolutepathname> is the standard doc directory (i.e. the same place
where the <relativepathname> files will be copied).
The <relativepathname> version has the hidden side effect of removing
the contents of the doc directory first (and thus your carefully installed
files).  The whole distinction which makes a special case for relative
paths is a crock in the first place ;-)