createdb: Fix quoting of --encoding, --lc-ctype and --lc-collate

createdb: Fix quoting of --encoding, --lc-ctype and --lc-collate

The original coding failed to properly quote those arguments, leading to
failures when using quotes in the values used.  As the quoting can be
encoding-sensitive, the connection to the backend needs to be taken
before applying the correct quoting.

Author: Michael Paquier
Reviewed-by: Daniel Gustafsson
Discussion: https://postgr.es/m/20200214041004[email protected]
Backpatch-through: 9.5