travis: Use trap and set -e errtrace

.travis/test_06_script.sh

@@ -40,20 +40,16 @@ BEGIN_FOLD configure
 DOCKER_EXEC ./configure --cache-file=../config.cache $BITCOIN_CONFIG_ALL $BITCOIN_CONFIG || ( cat config.log && false)
 END_FOLD
 
+set -o errtrace
+trap 'DOCKER_EXEC "cat ${TRAVIS_BUILD_DIR}/sanitizer-output/* 2> /dev/null"' ERR
+
 BEGIN_FOLD build
-DOCKER_EXEC make $MAKEJOBS $GOAL || (
-  echo "Build failure. Verbose build follows." && DOCKER_EXEC make $GOAL V=1
-  DOCKER_EXEC "cat ${TRAVIS_BUILD_DIR}/sanitizer-output/* 2> /dev/null"
-  false
-)
+DOCKER_EXEC make $MAKEJOBS $GOAL || ( echo "Build failure. Verbose build follows." && DOCKER_EXEC make $GOAL V=1 ; false )
 END_FOLD
 
 if [ "$RUN_UNIT_TESTS" = "true" ]; then
   BEGIN_FOLD unit-tests
-  DOCKER_EXEC LD_LIBRARY_PATH=$TRAVIS_BUILD_DIR/depends/$HOST/lib make $MAKEJOBS check VERBOSE=1 || (
-    DOCKER_EXEC "cat ${TRAVIS_BUILD_DIR}/sanitizer-output/* 2> /dev/null"
-    false
-  )
+  DOCKER_EXEC LD_LIBRARY_PATH=$TRAVIS_BUILD_DIR/depends/$HOST/lib make $MAKEJOBS check VERBOSE=1
   END_FOLD
 fi
 
@@ -63,9 +59,6 @@ fi
 
 if [ "$RUN_FUNCTIONAL_TESTS" = "true" ]; then
   BEGIN_FOLD functional-tests
-  DOCKER_EXEC test/functional/test_runner.py --ci --combinedlogslen=4000 --coverage --quiet --failfast ${extended} ${FUNCTIONAL_TESTS_CONFIG} || (
-    DOCKER_EXEC "cat ${TRAVIS_BUILD_DIR}/sanitizer-output/* 2> /dev/null"
-    false
-  )
+  DOCKER_EXEC test/functional/test_runner.py --ci --combinedlogslen=4000 --coverage --quiet --failfast ${extended} ${FUNCTIONAL_TESTS_CONFIG}
   END_FOLD
 fi