Update kernelspec.py

Updated comments to match `--user` flag use.

IPython/kernel/kernelspec.py

@@ -160,7 +160,7 b' class KernelSpecManager(HasTraits):'
         If ``kernel_name`` is not given, the basename of ``source_dir`` will
         be used.
         
-        If ``system`` is True, it will attempt to install into the systemwide
+        If ``user`` is False, it will attempt to install into the systemwide
         kernel registry. If the process does not have appropriate permissions,
         an :exc:`OSError` will be raised.
         
@@ -186,7 +186,7 b' class KernelSpecManager(HasTraits):'
         The kernelspec will be written pointing to the Python executable on
         which this is run.
         
-        If ``system`` is True, it will attempt to install into the systemwide
+        If ``user`` is False, it will attempt to install into the systemwide
         kernel registry. If the process does not have appropriate permissions, 
         an :exc:`OSError` will be raised.
         """