handle potentially absent win32api in launcher.py

IPython/parallel/apps/launcher.py

@@ -591,7 +591,8 b' def find_job_cmd():'
     if os.name=='nt':
         try:
             return find_cmd('job')
-        except FindCmdError:
+        except (FindCmdError, ImportError):
+            # ImportError will be raised if win32api is not installed
             return 'job'
     else:
         return 'job'