Omit mongod log messages.

MongoDB failures no longer allowed

.ci/travis-before-script.sh

@@ -8,5 +8,5 @@ elif [[ "${BIGCHAINDB_DATABASE_BACKEND}" == mongodb ]]; then
     wget http://downloads.mongodb.org/linux/mongodb-linux-x86_64-3.4.1.tgz -O /tmp/mongodb.tgz
     tar -xvf /tmp/mongodb.tgz
     mkdir /tmp/mongodb-data
-    ${PWD}/mongodb-linux-x86_64-3.4.1/bin/mongod --dbpath=/tmp/mongodb-data --replSet=rs0 &
+    ${PWD}/mongodb-linux-x86_64-3.4.1/bin/mongod --dbpath=/tmp/mongodb-data --replSet=rs0 &> /dev/null &
 fi

.ci/travis_script.sh

@@ -5,7 +5,7 @@ set -e -x
 if [[ -n ${TOXENV} ]]; then
   tox -e ${TOXENV}
 elif [[ "${BIGCHAINDB_DATABASE_BACKEND}" == mongodb ]]; then
-    pytest -vs --database-backend=mongodb --cov=bigchaindb
+    pytest -v --database-backend=mongodb --cov=bigchaindb
 else
   pytest -v -n auto --cov=bigchaindb
 fi

.travis.yml

@@ -12,8 +12,6 @@ env:
 
 matrix:
   fast_finish: true
-  allow_failures:
-  - env: BIGCHAINDB_DATABASE_BACKEND=mongodb
   exclude:
   - python: 3.4 
     env: TOXENV=flake8