1) Disable the PSQL feature entirely in server mode by default.

2) Remove the code that attempts to filter out commands.

refs #2341

docs/en_US/psql_tool.rst

@@ -10,10 +10,6 @@ PSQL tool allows user to connect to PostgreSQL/EDB Advanced server using psql te
 
 * PSQL will connect to the current connected database from browser tree.
 
-* PSQL utility does support execution of OS meta-commands by using "\\!". Due
-  to security concerns, we have disabled the execution of such commands in
-  pgAdmin. To enable OS meta-commands set ALLOW_PSQL_SHELL_COMMANDS = True in configuration.
-
 .. image:: images/psql_tool.png
     :alt: PSQL tool window
     :align: center