fix issue with GET on large object

Fixing a call to _drop_cache that had an extra parameter

A patch to this issue was first provided by Xw Huang(xwhuang@qnap.com)
in gluster-swift gerrit. I'm transferring the patch to swiftonfile.

Fixes issue #13

Signed-off-by: Thiago da Silva <thiago@redhat.com>
adding unit test that would have caught this issue

This chunk of code is only executed when reading a large file
(> 1014 * 1024), so the issue was never caught in our unit tests

refer to issue #13

Signed-off-by: Thiago da Silva <thiago@redhat.com>
adding functional test to cover same issue

functional test writes and read a large object to exercise
code that calls drop_cache after reading 1MB of data

Signed-off-by: Thiago da Silva <thiago@redhat.com>
adding functional test to cover same issue

functional test writes and read a large object to exercise
code that calls drop_cache after reading 1MB of data

Signed-off-by: Thiago da Silva <thiago@redhat.com>
Merge branch 'GET_failure' of github.com:thiagol11/swiftonfile into GET_failure
removing unused time module

Signed-off-by: Thiago da Silva <thiago@redhat.com>
Merge pull request #16 from thiagol11/GET_failure

fix issue with GET on large object