CI: unary operator expected error in log files (#26547)

Author: simonjayhawkins

ci/setup_env.sh

@@ -118,12 +118,12 @@ echo "conda list"
 conda list
 
 # Install DB for Linux
-if [ ${TRAVIS_OS_NAME} == "linux" ]; then
+if [ "${TRAVIS_OS_NAME}" == "linux" ]; then
   echo "installing dbs"
   mysql -e 'create database pandas_nosetest;'
   psql -c 'create database pandas_nosetest;' -U postgres
 else
-   echo "not using dbs on non-linux"
+   echo "not using dbs on non-linux Travis builds or Azure Pipelines"
 fi
 
 echo "done"