test-lib: make "-x" work with "--verbose-log"

The "-x" tracing option implies "--verbose". This is a
problem when running under a TAP harness like "prove", where
we need to use "--verbose-log" instead. Instead, let's
handle this the same way we do for --valgrind, including the
recent fix from 88c6e9d31c (test-lib: --valgrind should not
override --verbose-log, 2017-09-05). Namely, let's enable
--verbose only when we know there isn't a more specific
verbosity option indicated.

Note that we also have to tweak `want_trace` to turn it on
(previously we just lumped $verbose_log in with $verbose,
but now we don't necessarily auto-set the latter).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/test-lib.sh

@@ -264,7 +264,6 @@ do
 		shift ;;
 	-x)
 		trace=t
-		verbose=t
 		shift ;;
 	--verbose-log)
 		verbose_log=t
@@ -283,6 +282,11 @@ then
 	test -z "$verbose_log" && verbose=t
 fi
 
+if test -n "$trace" && test -z "$verbose_log"
+then
+	verbose=t
+fi
+
 if test -n "$color"
 then
 	# Save the color control sequences now rather than run tput
@@ -586,7 +590,9 @@ maybe_setup_valgrind () {
 }
 
 want_trace () {
-	test "$trace" = t && test "$verbose" = t
+	test "$trace" = t && {
+		test "$verbose" = t || test "$verbose_log" = t
+	}
 }
 
 # This is a separate function because some tests use