Change expected master boot string for netboot back

Author: plars

device-connectors/src/testflinger_device_connectors/devices/netboot/netboot.py

@@ -189,7 +189,7 @@ def is_master_image_booted(self):
         except Exception:
             # Any connection error will fail through the normal path
             pass
-        if "Testflinger Test Device Imager" in str(data):
+        if "Snappy Test Device Imager" in str(data):
             return True
         else:
             return False