btrfs-progs: doc: autoformat user-supplied arguments by sed

Convert all values enclosed between <...> to italic before it goes to
asciidoc processor.

Signed-off-by: David Sterba <dsterba@suse.cz>

Documentation/Makefile

@@ -85,10 +85,11 @@ clean:
 %.8 : %.xml 
 	$(QUIET_XMLTO)$(RM) $@ && \
 	$(XMLTO) -m $(MANPAGE_XSL) $(XMLTO_EXTRA) man $<
-
 %.xml : %.txt asciidoc.conf
-	$(QUIET_ASCIIDOC)$(RM) $@+ $@ && \
+	$(QUIET_ASCIIDOC)$(RM) $@.tmp[12] $@ && \
+	sed -e "s/\(<[^>]\+>\)/'\1'/g" < $< > $@.tmp1 && \
 	$(ASCIIDOC) -b docbook -d manpage -f asciidoc.conf \
 		$(ASCIIDOC_EXTRA) -abtrfs_version=$(BTRFS_VERSION) \
-		-o $@+ $< && \
-	mv $@+ $@
+		-o $@.tmp2 $@.tmp1 && \
+	mv $@.tmp2 $@ && \
+	rm -f -- $@.tmp1