Eager upgrade works also in editable mode. (#13589)

The recent change #13409 introduced common installation script
but one case turned out to be not working. Installing Airflow
in editable mode with eager upgrade fails on building production
image (the CI image effectively did not have airflow installed
in editable mode, which it should).

This PR fixes that.

scripts/docker/install_airflow.sh

@@ -56,6 +56,13 @@ function install_airflow() {
         pip install ${AIRFLOW_INSTALL_USER_FLAG} --upgrade --upgrade-strategy eager \
             "${AIRFLOW_INSTALLATION_METHOD}[${AIRFLOW_EXTRAS}]${AIRFLOW_INSTALL_VERSION}" \
             ${EAGER_UPGRADE_ADDITIONAL_REQUIREMENTS}
+        if [[ ${AIRFLOW_INSTALL_EDITABLE_FLAG} != "" ]]; then
+            # Remove airflow and reinstall it using editable flag
+            # We can only do it when we install airflow from sources
+            pip uninstall apache-airflow --yes
+            pip install ${AIRFLOW_INSTALL_EDITABLE_FLAG} \
+                "${AIRFLOW_INSTALLATION_METHOD}[${AIRFLOW_EXTRAS}]${AIRFLOW_INSTALL_VERSION}"
+        fi
         # make sure correct PIP version is used
         pip install ${AIRFLOW_INSTALL_USER_FLAG} --upgrade "pip==${AIRFLOW_PIP_VERSION}"
         pip check || ${CONTINUE_ON_PIP_CHECK_FAILURE}