Fixes 'sys.exit() doesn't do what you think it does'

Two problems here:
1. is_online() was testing the wrong thing so was always True

2. sys.exit() actually throws exceptions on threads which are not the thread
that made the call.  If you have a catchall except statement this will also
catch the exit signal.  So the application never exits.

In the pool manager's case the signal handler is running on a separate thread.
The signal handler thread executes sys.exit() and if the main thread is in
a block with a catchall except it hangs.  Fixed this by narrowing the
exception list caught.

Fixes bug #1078738

Change-Id: I9f561b9d3794d1f6fab84c116f69e7fe97464e85

libra/mgm/drivers/hp_rest/driver.py

@@ -50,7 +50,7 @@ class HPRestDriver(MgmDriver):
         return usage['free']
 
     def is_online(self):
-        return self.is_online
+        return self.online
 
     def get_node_list(self, limit, marker):
         return self._get('{url}/devices'.format(url=self.url))
@@ -80,7 +80,7 @@ class HPRestDriver(MgmDriver):
     def _get(self, url):
         try:
             r = requests.get(url, verify=False)
-        except:
+        except requests.exceptions.RequestException:
             self.logger.error('Exception communicating to server: {exc}'
                               .format(exc=sys.exc_info()[0]))
             return False, None
@@ -94,7 +94,7 @@ class HPRestDriver(MgmDriver):
     def _post(self, url, node_data):
         try:
             r = requests.post(url, data=json.dumps(node_data), verify=False)
-        except:
+        except requests.exceptions.RequestException:
             self.logger.error('Exception communicating to server: {exc}'
                               .format(exc=sys.exc_info()[0]))
             return False, None

libra/mgm/nova.py

@@ -18,6 +18,7 @@ import sys
 import urllib
 
 from novaclient import client
+from novaclient import exceptions
 
 
 class NotFound(Exception):
@@ -52,7 +53,7 @@ class Node(object):
         node_id = uuid.uuid1()
         try:
             body = self._create(node_id)
-        except:
+        except exceptions.ClientException:
             return False, 'Error creating node {nid} exception {exc}'.format(
                 nid=node_id, exc=sys.exc_info()[0]
             )
@@ -80,7 +81,7 @@ class Node(object):
         """ delete a node """
         try:
             resp = self._delete(node_id)
-        except:
+        except exceptions.ClientException:
             return False, 'Error deleting node {nid} exception {exc}'.format(
                 nid=node_id, exc=sys.exc_info()[0]
             )