Don't crash if home directory isn't writable.

Most of our CookieJar.save() calls were wrapped in a try/except to catch
IOErrors, but the one in http_put wasn't. This meant if the home directory
wasn't writable (for example, in some automated post-commit scenarios),
post-review would crash with an uncaught exception. Trivial fix.

Fixes bug 2344.

rbtools/postreview.py

@@ -796,7 +796,10 @@ def http_put(self, path, fields):
         try:
             r = HTTPRequest(url, body, headers, method='PUT')
             data = urllib2.urlopen(r).read()
-            self.cookie_jar.save(self.cookie_file)
+            try:
+                self.cookie_jar.save(self.cookie_file)
+            except IOError, e:
+                debug('Failed to write cookie file: %s' % e)
             return data
         except urllib2.HTTPError, e:
             # Re-raise so callers can interpret it.
@@ -821,7 +824,10 @@ def http_delete(self, path):
         try:
             r = HTTPRequest(url, method='DELETE')
             data = urllib2.urlopen(r).read()
-            self.cookie_jar.save(self.cookie_file)
+            try:
+                self.cookie_jar.save(self.cookie_file)
+            except IOError, e:
+                debug('Failed to write cookie file: %s' % e)
             return data
         except urllib2.HTTPError, e:
             # Re-raise so callers can interpret it.