chore(python): remove one remaining extra bash line (#565)

To avoid generating bogus PRs

Co-authored-by: Jeffrey Rennie <rennie@google.com>

Author: cguardia

synthtool/gcp/templates/python_library/.kokoro/release.sh

@@ -13,8 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-#!/bin/bash
-
 set -eo pipefail
 
 # Start the releasetool reporter