Pin Monit CI to a specific release (#1490)

We pin to the master branch of Monit, which introduced [a commit
](https://bitbucket.org/tildeslash/monit/commits/
d7e47c583c41002e9764481b256c1c786dcaee90)
today that blocks our CI. This PR unblocks things and pins to the latest
release of Monit to make our CI more stable.

tests/ci/integration/run_monit_integration.sh

@@ -4,6 +4,8 @@
 
 source tests/ci/common_posix_setup.sh
 
+MONIT_VERSION_TAG="release-5-33-0"
+
 # Set up environment.
 
 # SYS_ROOT
@@ -21,6 +23,15 @@ MONIT_BUILD_FOLDER="${SCRATCH_FOLDER}/monit-aws-lc"
 AWS_LC_BUILD_FOLDER="${SCRATCH_FOLDER}/aws-lc-build"
 AWS_LC_INSTALL_FOLDER="${SCRATCH_FOLDER}/aws-lc-install"
 
+function monit_upgrade_reminder() {
+  LATEST_MONIT_VERSION_TAG=`git describe --tags --abbrev=0`
+  if [[ "${LATEST_MONIT_VERSION_TAG}" != "${MONIT_VERSION_TAG}" ]]; then
+    aws cloudwatch put-metric-data --namespace AWS-LC --metric-name MonitVersionUpdate --value 1
+  else
+    aws cloudwatch put-metric-data --namespace AWS-LC --metric-name MonitVersionUpdate --value 0
+  fi
+}
+
 function monit_build() {
   ./bootstrap  
   ./configure --with-ssl-static="${AWS_LC_INSTALL_FOLDER}"
@@ -41,15 +52,15 @@ mkdir -p ${SCRATCH_FOLDER}
 rm -rf "${SCRATCH_FOLDER:?}"/*
 cd ${SCRATCH_FOLDER}
 
-git clone https://bitbucket.org/tildeslash/monit.git ${MONIT_SRC_FOLDER} --depth 1
+git clone https://bitbucket.org/tildeslash/monit.git ${MONIT_SRC_FOLDER} -b ${MONIT_VERSION_TAG} --depth 1
 mkdir -p ${AWS_LC_BUILD_FOLDER} ${AWS_LC_INSTALL_FOLDER} ${MONIT_BUILD_FOLDER}
 ls
 
 aws_lc_build "$SRC_ROOT" "$AWS_LC_BUILD_FOLDER" "$AWS_LC_INSTALL_FOLDER" -DBUILD_TESTING=OFF -DBUILD_TOOL=OFF -DCMAKE_BUILD_TYPE=RelWithDebInfo -DBUILD_SHARED_LIBS=0
 
 # Build monit from source.
 pushd ${MONIT_SRC_FOLDER}
-
+monit_upgrade_reminder
 monit_build
 monit_run_tests
 popd