Don't create a swapfile if there is not enough disk space. (#1850)
Don't create a swapfile if there is not enough disk space. (#1850)

This change adds a check to the Datalab instance startup script where
the swapfile creation/usage is prevented if the free disk space is not at
least 10x the size of memory.

This is the first step towards addressing #1839, but the full issue
won't be fixed until we also provide a way to turn off swap entirely
for users who do not want it.
googledatalab/datalab,parthea/datalab,googledatalab/datalab,parthea/datalab,parthea/datalab,googledatalab/datalab,googledatalab/datalab,parthea/datalab,parthea/datalab,parthea/datalab,googledatalab/datalab,googledatalab/datalab