tests: Make the gb test work with srcdir != builddir

* Disable color and printing the filename of the stderr log target,
  update the results
* Add the .ok, .err and .sh files to the extra_dist
* Execute the shell script from the source directory
diff --git a/tests/testsuite.at b/tests/testsuite.at
index dd22c32..360f846 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -13,7 +13,7 @@
 AT_KEYWORDS([bssgp-fc])
 cat $abs_srcdir/gb/bssgp_fc_tests.ok > expout
 cat $abs_srcdir/gb/bssgp_fc_tests.err > experr
-AT_CHECK([$abs_top_builddir/tests/gb/bssgp_fc_tests.sh $abs_top_builddir/tests/gb], [], [expout], [experr])
+AT_CHECK([$abs_top_srcdir/tests/gb/bssgp_fc_tests.sh $abs_top_builddir/tests/gb], [], [expout], [experr])
 AT_CLEANUP
 
 AT_SETUP([bits])