Fix download error reporting

Threaded downloads now
store the exception for passing
to the caller.

Change-Id: Ibe4a7a267b04a2775ad3775dd904a4e3c7520ebb

pyghmi/ipmi/oem/lenovo/imm.py

@@ -1018,6 +1018,8 @@ class XCCClient(IMMClient):
                 progress({'phase': 'download',
                           'progress': 100 * self.wc.get_download_progress()})
             self._refresh_token()
+        if fd.exc:
+            raise fd.exc
         if progress:
             progress({'phase': 'complete'})
         return savefile

pyghmi/redfish/oem/lenovo/xcc.py

@@ -716,6 +716,8 @@ class OEMHandler(generic.OEMHandler):
                 progress({'phase': 'download',
                           'progress': 100 * self.wc.get_download_progress()})
             self._refresh_token()
+        if fd.exc:
+            raise fd.exc
         if progress:
             progress({'phase': 'complete'})
         return savefile

pyghmi/util/webclient.py

@@ -74,10 +74,14 @@ class FileDownloader(threading.Thread):
         self.wc = webclient
         self.url = url
         self.savefile = savefile
+        self.exc = None
         super(FileDownloader, self).__init__()
 
     def run(self):
-        self.wc.download(self.url, self.savefile)
+        try:
+            self.wc.download(self.url, self.savefile)
+        except Exception as e:
+            self.exc = e
 
 
 def get_upload_form(filename, data, formname, otherfields):