Fix typo in docstring (repeated word).

9 jobs for master in 2 minutes and 33 seconds (queued for 9 seconds)
Name Stage Failure
failed
test:lib Test
	  9 - OlmDecrypt (Failed)
10 - OlmSha256 (Failed)
11 - OlmSignature (Failed)
12 - OlmUsingMalloc (Failed)
13 - Session (Failed)
14 - PublicKey (Failed)
15 - SAS (Failed)
Cleaning up file based variables
ERROR: Job failed: command terminated with exit code 1