unable to use vault password file with multiple lines

[d4e-sluksch]

After upgrading an old instance of rundeck to version 5.4.0 we had the problem, that the decryption using our vault secret was not possible anymore.
While investigating the problem, we found an issue, facing the same problem (#362). Using the version 3.2.10 fixed our problem.
After testing more, we figured out, that our vault password file containing multiple lines triggered the bug. After analysing the changes between version 3.2.10 and 3.2.11 we were able to figure out, that reading the vault secret through vault-client.py causes the issue, because this script only reads exactly one line as password (see v3.2.10...v3.2.11#diff-ff0530df30ccd0765c8039337370afda285e104f8e5fd53a3f0925469a5482f6R15)