Remove unused (Travis CI) prometheus_rsa.enc file

This got added as part of
7b70381.
When Travis was removed, it never got removed.

Signed-off-by: Julius Volz <[email protected]>

Author: juliusv

.gitignore

@@ -13,8 +13,6 @@ crash.log
 # macOS artifacts
 .DS_Store
 
-prometheus_rsa
-
 # Ruby artifacts
 .bundle/
 vendor/