Make zwave component user sane defaults. (#1891)

Change the zwave config default path to be valid in all but rare
edge cases. This will let that config value be truely optional.

Also check that libopenzwave is installed and print a warrning if
it cannot be found pointing at the site.

homeassistant/components/zwave.py

@@ -6,7 +6,6 @@ https://home-assistant.io/components/zwave/
 """
 import logging
 import os.path
-import sys
 import time
 from pprint import pprint
 
@@ -25,8 +24,6 @@ DEFAULT_CONF_USB_STICK_PATH = "/zwaveusbstick"
 CONF_DEBUG = "debug"
 CONF_POLLING_INTERVAL = "polling_interval"
 CONF_POLLING_INTENSITY = "polling_intensity"
-DEFAULT_ZWAVE_CONFIG_PATH = os.path.join(sys.prefix, 'share',
-                                         'python-openzwave', 'config')
 
 # How long to wait for the zwave network to be ready.
 NETWORK_READY_WAIT_SECS = 30
@@ -175,10 +172,20 @@ def setup(hass, config):
     # pylint: disable=global-statement, import-error
     global NETWORK
 
+    try:
+        import libopenzwave
+    except ImportError:
+        _LOGGER.error("You are missing required dependency Python Open "
+                      "Z-Wave. Please follow instructions at: "
+                      "https://home-assistant.io/components/zwave/")
+        return False
     from pydispatch import dispatcher
     from openzwave.option import ZWaveOption
     from openzwave.network import ZWaveNetwork
 
+    default_zwave_config_path = os.path.join(os.path.dirname(
+        libopenzwave.__file__), 'config')
+
     # Load configuration
     use_debug = str(config[DOMAIN].get(CONF_DEBUG)) == '1'
     customize = config[DOMAIN].get(CONF_CUSTOMIZE, {})
@@ -188,7 +195,7 @@ def setup(hass, config):
         config[DOMAIN].get(CONF_USB_STICK_PATH, DEFAULT_CONF_USB_STICK_PATH),
         user_path=hass.config.config_dir,
         config_path=config[DOMAIN].get('config_path',
-                                       DEFAULT_ZWAVE_CONFIG_PATH),)
+                                       default_zwave_config_path),)
 
     options.set_console_output(use_debug)
     options.lock()