Several problems: some invalid <command> etc. directives
in the tapset embedded docs; some analysis about the
non-generation of the pdf; some cleanup of the generated
man pages.
* configure.ac (BUILD_PDFREFDOCS): Correct condition typo, but still
leave disabled.
* doc/SystemTap_Tapset_Reference/Makefile.am (XMLTOMANPARMS): Add,
to disable noise "AUTHORS" / "COPYRIGHT" sections.
* tapset/*.stp: Removed several docbook-y markup that is not valid
in kerneldoc.