lttng-babeltrace: fix license information

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/lttng-babeltrace/lttng-babeltrace.mk

@@ -7,7 +7,7 @@
 LTTNG_BABELTRACE_SITE    = http://lttng.org/files/babeltrace
 LTTNG_BABELTRACE_VERSION = 1.2.2
 LTTNG_BABELTRACE_SOURCE  = babeltrace-$(LTTNG_BABELTRACE_VERSION).tar.bz2
-LTTNG_BABELTRACE_LICENSE = MIT; LGPL2.1 for include/babeltrace/list.h; GPLv2+ for test code
+LTTNG_BABELTRACE_LICENSE = MIT; LGPLv2.1 for include/babeltrace/list.h; GPLv2 for test code
 LTTNG_BABELTRACE_LICENSE_FILES = mit-license.txt gpl-2.0.txt LICENSE
 
 LTTNG_BABELTRACE_DEPENDENCIES = popt util-linux libglib2