babeltrace: Fix case where ${B} != ${S}

Autotools need to run in ${S}.

(From OE-Core rev: 2a64b618755cc1b97c21c8dc30ffd7d0938e9f91)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-kernel/lttng/babeltrace_1.0.3.bb

@@ -19,5 +19,5 @@ SRC_URI = "git://git.efficios.com/babeltrace.git;protocol=git"
 S = "${WORKDIR}/git"
 
 do_configure_prepend () {
-	${S}/bootstrap
+	( cd ${S}; ${S}/bootstrap )
 }