GIT_SILENT [Octave] Minor cmake fix

1 job for master in 3 minutes and 17 seconds
Status Job ID Name Coverage
  Build
failed #55450
linux kf5-qt5 qt5.12

00:03:17

 
Name Stage Failure
failed
linux kf5-qt5 qt5.12 Build
    return self.do_open(http.client.HTTPSConnection, req,
File "/usr/lib64/python3.8/urllib/request.py", line 1353, in do_open
raise URLError(err)
urllib.error.URLError: <urlopen error [Errno -3] Temporary failure in name resolution>
Uploading artifacts for failed job
Uploading artifacts...
WARNING: JUnitTestResults.xml: no matching files
ERROR: No files to upload
ERROR: Job failed: exit code 1