Remove branch name env variable in periodic e2e tests (#1595)

* remove branch name env variable

* adding git checkout commitId

perfmetrics/scripts/continuous_test/gcp_ubuntu/e2e_tests/build.sh

@@ -22,11 +22,11 @@ readonly RUN_E2E_TESTS_ON_INSTALLED_PACKAGE=true
 cd "${KOKORO_ARTIFACTS_DIR}/github/gcsfuse"
 echo "Building and installing gcsfuse..."
 # Get the latest commitId of yesterday in the log file. Build gcsfuse and run
-commitId=$(git log origin/$BRANCH_NAME --before='yesterday 23:59:59' --max-count=1 --pretty=%H)
+commitId=$(git log --before='yesterday 23:59:59' --max-count=1 --pretty=%H)
 ./perfmetrics/scripts/build_and_install_gcsfuse.sh $commitId
 
-# To execute tests for a specific branch, ensure you've checked out from that branch first.
-git checkout origin/$BRANCH_NAME
+# To execute tests for a specific commitId, ensure you've checked out from that commitId first.
+git checkout $commitId
 
 echo "Running e2e tests on installed package...."
 # $1 argument is refering to value of testInstalledPackage

perfmetrics/scripts/continuous_test/gcp_ubuntu/e2e_tests/e2e-tests-master.cfg

@@ -12,11 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-env_vars {
-  key: "BRANCH_NAME"
-  value: "master"
-}
-
 action {
   define_artifacts {
     regex: "gcsfuse-failed-integration-test-logs-*"

perfmetrics/scripts/continuous_test/gcp_ubuntu/e2e_tests/e2e-tests-release.cfg

@@ -12,11 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-env_vars {
-  key: "BRANCH_NAME"
-  value: "read_cache_release"
-}
-
 action {
   define_artifacts {
     regex: "gcsfuse-failed-integration-test-logs-*"