Make use of awesome-client commands

This uses the new support introduced in f0f31bc305 in the docs and in
tests/run.sh, removing an useless use of cat/echo.

Signed-off-by: Uli Schlachter <psychon@znc.in>

docs/90-FAQ.md

@@ -304,10 +304,10 @@ the upper right corner of the screen.
 ### How to restart or quit awesome?
 
 You can use the keybinding "Mod4+Ctrl+r" or by selecting restart in the menu.
-You could call `awesome.restart` either from the Lua prompt widget, or by
-passing it to `awesome-client`:
+You could call `awesome.restart` either from the Lua prompt widget, or via
+`awesome-client`:
 
-    $ echo 'awesome.restart()' | awesome-client
+    $ awesome-client 'awesome.restart()'
 
 You can also send the `SIGHUP` signal to the awesome process. Find the PID using
 `ps`, `pgrep` or use `pkill`:

tests/run.sh

@@ -188,7 +188,7 @@ start_awesome() {
     cd - >/dev/null
 
     # Wait until the interface for awesome-client is ready (D-Bus interface).
-    wait_until_success "wait for awesome startup via awesome-client" "echo 'return 1' | DISPLAY=$D '$AWESOME_CLIENT' 2>&1"
+    wait_until_success "wait for awesome startup via awesome-client" "DISPLAY=$D '$AWESOME_CLIENT' 'return 1' 2>&1"
 }
 
 # Count errors.