library: reverting tmpfs subtraction from cached (18-FEB-2014)

The subtraction was marked as reinforcing the misconception,
that memory in the page cache can be considered free.
The Cached value is not a sum of page cache and tmpfs,
as the tmpfs memory lives in the page cache and therefore
it's an inseparable part of it.

proc/sysinfo.c

@@ -682,8 +682,6 @@ nextline:
   }
   kb_swap_used = kb_swap_total - kb_swap_free;
   kb_main_used = kb_main_total - kb_main_free;
-  /* "Cached" includes "Shmem" - we want only the page cache here */
-  kb_main_cached -= kb_main_shared;
 }
 
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