[FIX] hw_{scanner,escpos}: ensure we always release the lock.

[FIX] hw_scanner: mark the thread as deamon.

bzr revid: chs@openerp.com-20140329144146-utr8gexna4un65u1

addons/hw_escpos/controllers/main.py

@@ -51,11 +51,10 @@ class EscposDriver(Thread):
         return connected
 
     def lockedstart(self):
-        self.lock.acquire()
-        if not self.isAlive():
-            self.daemon = True
-            self.start()
-        self.lock.release()
+        with self.lock:
+            if not self.isAlive():
+                self.daemon = True
+                self.start()
     
     def get_escpos_printer(self):
         try:

addons/hw_scanner/controllers/main.py

@@ -88,10 +88,10 @@ class Scanner(Thread):
         }
 
     def lockedstart(self):
-        self.lock.acquire()
-        if not self.isAlive():
-            self.start()
-        self.lock.release()
+        with self.lock:
+            if not self.isAlive():
+                self.daemon = True
+                self.start()
 
     def set_status(self, status, message = None):
         if status == self.status['status']: