Set LD_LIBRARY_PATH consistently in travis tests

Makes it possible to substitute bitcoin-qt and bitcoin-node in place of
bitcoind in python tests, or to link bitcoind differently.

Author: ryanofsky

.travis/test_06_script_b.sh

@@ -16,13 +16,13 @@ fi
 
 if [ "$RUN_FUNCTIONAL_TESTS" = "true" ]; then
   BEGIN_FOLD functional-tests
-  DOCKER_EXEC test/functional/test_runner.py --ci --combinedlogslen=4000 ${TEST_RUNNER_EXTRA} --quiet --failfast
+  DOCKER_EXEC LD_LIBRARY_PATH=$TRAVIS_BUILD_DIR/depends/$HOST/lib test/functional/test_runner.py --ci --combinedlogslen=4000 ${TEST_RUNNER_EXTRA} --quiet --failfast
   END_FOLD
 fi
 
 if [ "$RUN_FUZZ_TESTS" = "true" ]; then
   BEGIN_FOLD fuzz-tests
-  DOCKER_EXEC test/fuzz/test_runner.py -l DEBUG ${DIR_FUZZ_IN}
+  DOCKER_EXEC LD_LIBRARY_PATH=$TRAVIS_BUILD_DIR/depends/$HOST/lib test/fuzz/test_runner.py -l DEBUG ${DIR_FUZZ_IN}
   END_FOLD
 fi