Revert of Return correct disk free/available size when FS is mounted with size = 0 (patchset #4 id:60001 of https://codereview.chromium.org/2152283003/ )

Reason for revert:
Breaks host_forwarder on WebRTC bots: https://build.chromium.org/p/tryserver.webrtc/builders/android_arm64_rel/builds/9516/steps/compile/logs/stdio:

obj.host/chromium/src/base/base.sys_info_posix.o: In function `base::(anonymous namespace)::GetDiskSpaceInfo(base::FilePath const&, long*, long*)':
../../chromium/src/base/sys_info_posix.cc:(.text._ZN4base12_GLOBAL__N_116GetDiskSpaceInfoERKNS_8FilePathEPlS4_+0x4c): undefined reference to `base::GetFileSystemType(base::FilePath const&, base::FileSystemType*)'

I really don't know why it goes into the OS_LINUX branch since the bot is an Android bot though. host_forwarder is in the Chromium codebase. I would have understood it if it was WebRTC code since we have different macros (e.g. WEBRTC_LINUX) which would explain this breakage, but it appears to break host_forwarder.

Note that WebRTC will be on GYP a couple more weeks, so this could be a gyp-only problem. Presumably you'll be able to repro if you generate with gyp and try to build host_forwarder in a chromium checkout.

Original issue's description:
> Return correct disk free/available size when FS is mounted with size = 0
>
> When tmpfs is mounted with size = 0 (i.e. without any limit), then statvfs
> will return 0 for f_bfree, f_bavail, and f_blocks. Catch this case and return
> max_int64 instead.
>
> BUG=628710
>
> Committed: https://crrev.com/6c917630660164bb28d57f31b970b38591c0b8b1
> Cr-Commit-Position: refs/heads/master@{#406473}

TBR=thestig@chromium.org,reveman@chromium.org,sriramsr@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=628710

Review-Url: https://codereview.chromium.org/2168843002
Cr-Commit-Position: refs/heads/master@{#406825}