Modifying a file without changing its size results in confusing behavior.

[jaccarmac]

To dupe:

1. Create a file with some contents.
2. drive push thatfile
3. Change a single character in thatfile.
4. drive push thatfile

Expected behavior: thatfile is updated on Drive and its modification time is changed there as well.
Actual behavior: thatfile has its modification time on Drive updated but the contents do not change. If the versions are inspected on Drive there is no version corresponding to the updated modification time.

Noticed this due to my propensity to store git repos in Drive. Since they contain many files with contents which change without the size of the file changing, I began to notice the issue causing strangeness.

[jaccarmac]

Closing as a duplicate of #710.