shell: Fix port extraction after a bracket-enclosed address.

More consistent with address extraction.

shell/caucase.sh

@@ -784,7 +784,7 @@ EOF
                     printf "%s\\n" "$ca_netloc" | sed "s!^\\(.*\\]\\).*!\\1!"
                   )"
                   ca_port="$(
-                    printf "%s\\n" "$ca_netloc" | sed "s!^[^\\]]*\\]:!!"
+                    printf "%s\\n" "$ca_netloc" | sed "s!.*\\]:!!"
                   )"
                 ;;
                 *\]*)