top buffers/cached values are bogus on new kernels

[Timo Teras]

Hi,

On new kernels (3.14+) the buffers and cached fields for 'top' applet
are bogus.

procps/top.c:display_header() parses /proc/meminfo directly, and it
works only if the expected fields come in the expected order. For 3.14
MemAvailable field was added after MemFree[1]; and that broke the code.
It would probably make sense to write the code in more generic form so
the order of the fields does not matter.

- Timo

[1] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=34e431b0ae398fc54ea69ff85ec700722c9da773