aux: fix selecting lvmconf values

For older bashes (i.e. rhel5) code can't use internal bash arrays
and uses old-school greps and sorts to create configuration file.
But the split of value was mismatching names with same prefix
so  i.e.

devices/scan
devices/scan_lvs

was matching always the later one - fix this by expecting
whitespace or '=' after the name.

test/lib/aux.sh

@@ -1296,7 +1296,7 @@ EOF
 			echo "$s {"
 			local k
 			for k in $(grep ^"$s"/ "$config_values" | cut -f1 -d= | sed -e 's, *$,,' | sort | uniq); do
-				grep "^$k" "$config_values" | tail -n 1 | sed -e "s,^$s/,	 ," || true
+				grep "^$k[ =]" "$config_values" | tail -n 1 | sed -e "s,^$s/,	 ," || true
 			done
 			echo "}"
 			echo