Only quote the quote characters in xml attributes

Only quote the quote characters in xml attributes

The quoting of single and double quotes is only necessary for
attributes, and is irritating for other fields in that it makes the
fields almost unreadable in the xml file.  Single quotes in particular
are common, and turning "it's" into "it's" is just not reasonable
for dive notes etc.

So add a flag to whether the xml quoting is for an attribute or not, and
take that into account.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>