Werk #15559: mk_oracle: Always use TNS_ALIAS when present

This werk may be relevant for you, in case:

• you want to monitor remote instances
• you are using a TNS_ALIAS to reach the remote instance

Previously, a TNS_ALIAS from mk_oracle.cfg was pinged by the plugin with tnsping in order to verify that this alias can be reached. However, this needs the tool tnsping installed with the oracle client, which is not shipped per default.

A failure led to silently ignoring the TNS_ALIAS and falling back to a potentially invalid connection string which is passed to sqlplus. The plugin now assumes that the given TNS_ALIAS can be reached and uses it.

To the list of all Werks