package/gnuradio: bump to version 3.8.0.0

package/gnuradio: bump to version 3.8.0.0

Since 2019/08/09 a new version of gnuradio is available.
This patch bump to this version with some modifications:
- suppress the applied patch 0001-socket_pdu_impl.cc-fix-build-with-boost-1.70.0.patch
- backport patch to have boost unit_test_framework optional instead of mandatory:
  https://github.com/gnuradio/gnuradio/pull/2927
- backport patch to fix neon version detection:
  https://github.com/gnuradio/volk/pull/319
- add boost atomic (used by pmt), log4cpp (now mandatory) and gmp as dependencies
- suppress the no more available BR2_PACKAGE_GNURADIO_LOG, since log4cpp is mandatory. Since this
  option is now always true no need to add an entry in legacy.
- suppress all workaround for neon. Now volk is able to detect correctly neon
  version.
- add explictly path to python interpreter

Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>