tests: update test-largefiles-small-disk to pass our import checker

tests/test-largefiles-small-disk.t

@@ -1,71 +1,74 b''
 Test how largefiles abort in case the disk runs full
 
   $ cat > criple.py <<EOF
-  > import os, errno, shutil
+  > from __future__ import absolute_import
+  > import errno
+  > import os
+  > import shutil
   > from mercurial import util
   > #
   > # this makes the original largefiles code abort:
   > _origcopyfileobj = shutil.copyfileobj
   > def copyfileobj(fsrc, fdst, length=16*1024):
   >     # allow journal files (used by transaction) to be written
   >     if 'journal.' in fdst.name:
   >         return _origcopyfileobj(fsrc, fdst, length)
   >     fdst.write(fsrc.read(4))
   >     raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))
   > shutil.copyfileobj = copyfileobj
   > #
   > # this makes the rewritten code abort:
   > def filechunkiter(f, size=131072, limit=None):
   >     yield f.read(4)
   >     raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))
   > util.filechunkiter = filechunkiter
   > #
   > def oslink(src, dest):
   >     raise OSError("no hardlinks, try copying instead")
   > util.oslink = oslink
   > EOF
 
   $ echo "[extensions]" >> $HGRCPATH
   $ echo "largefiles =" >> $HGRCPATH
 
   $ hg init alice
   $ cd alice
   $ echo "this is a very big file" > big
   $ hg add --large big
   $ hg commit --config extensions.criple=$TESTTMP/criple.py -m big
   abort: No space left on device
   [255]
 
 The largefile is not created in .hg/largefiles:
 
   $ ls .hg/largefiles
   dirstate
 
 The user cache is not even created:
 
   >>> import os; os.path.exists("$HOME/.cache/largefiles/")
   False
 
 Make the commit with space on the device:
 
   $ hg commit -m big
 
 Now make a clone with a full disk, and make sure lfutil.link function
 makes copies instead of hardlinks:
 
   $ cd ..
   $ hg --config extensions.criple=$TESTTMP/criple.py clone --pull alice bob
   requesting all changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   updating to branch default
   getting changed largefiles
   abort: No space left on device
   [255]
 
 The largefile is not created in .hg/largefiles:
 
   $ ls bob/.hg/largefiles
   dirstate