quote bash variables when passing them to xsltproc

[Pierre Labastie]

When we have something like:

--stringparam param1 $PARAM1 \
--stringparam param2 $PARAM2

and the variable PARAM1 is empty, what is passed to the xsl program is:

• param1 contains --stringparam
• param2 is taken as the name of an external entity to be read by the program.

and the following stringparam's have bogus values (if they have any). At least, this should be changed to:

--stringparam param1 "$PARAM1" \
--stringparam param2 "$PARAM2"

but it'd be better to test whether those variables are empty.

[Pierre Labastie]

fixed in trunk at r3970, and in 2.4 branch at r3971