volume: pulse-detection: explicitly try the "pulse" device

Because it's available on some systems (for which pulse is the right
option), but not the default, so `amixer info` will not give the right
result. When this command succeeds, there is no more need to check the
output.

Additionally removed a wrong test bracket (not neccessary and not
working for all bash versions).

volume/volume

@@ -23,9 +23,9 @@
 # For ALSA users, you may use "default" for your primary card
 # or you may use hw:# where # is the number of the card desired
 MIXER="default"
-if [ command -v pulseaudio >/dev/null 2>&1 && pulseaudio --check ] ; then
+if command -v pulseaudio >/dev/null 2>&1 && pulseaudio --check ; then
     # pulseaudio is running, but not all installations use "pulse"
-    if [ "$(amixer info | head -1 | cut -d ' ' -f 2)" == "pulse" ] ; then
+    if amixer -D pulse info >/dev/null 2>&1 ; then
         MIXER="pulse"
     fi
 fi