Convert subprocess to i3 exec call

i3-switcher.py

@@ -12,7 +12,6 @@ import glob
 from operator import itemgetter
 import ipc
 import alsaaudio
-import subprocess
 
 battery_warn = 5
 battery_poweroff = 3
@@ -144,9 +143,9 @@ def main(argv=None):
             batt_perc_overall = max(batt_percs)
             if batt_perc_overall<=battery_warn and int(batt_perc_overall)<int(last_batt_perc):
                 last_batt_perc = batt_perc_overall
-                subprocess.call(["i3-nagbar", "-m", "Battery low (%s)" % ", ".join("%s%%" % p for p in batt_percs)], stdin=DEVNULL, stdout=DEVNULL)
+                i3command.command(ipc.COMMAND, 'exec i3-nagbar -m "Battery low (%s)"' % ' '.join("%s%%" % p for p in batt_percs))
             if batt_perc_overall<=battery_poweroff:
-                subprocess.call(["/usr/sbin/poweroff"], stdin=DEVNULL, stdout=DEVNULL)
+                i3command.command(ipc.COMMAND, 'exec /usr/sbin/poweroff')
 
         # Date/time
         out.append({"name": "datetime", "full_text": datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"), "color": "#%06x" % color})