orbit2: Update LICENSE field version to GPLv2

* Updated LICENSE field version from generic GPL to GPLv2+ to
  reflect the real license version.
* This change was based on setting in oe-core as well as code
  inspection.
* Update submitted to oe-core as well.

Signed-off-by: Chase Maupin <Chase.Maupin@ti.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>

recipes/gnome/orbit2_2.14.17.bb

@@ -1,5 +1,9 @@
 require orbit2.inc
 
+LICENSE = "GPLv2+"
+
+PR = "r1"
+
 SRC_URI += "file://disable-ipv6.patch"
 noipv6 = "${@base_contains('DISTRO_FEATURES', 'ipv6', '', '-DDISABLE_IPV6', d)}"
 EXTRA_OEMAKE_append = " 'CFLAGS=${CFLAGS} ${noipv6}'"