This builds on top of recently introduced fscommon.ParseError.
Errors returned from parsers (mostly ones used by GetStats()) are all
different, and many are incomplete. For example, in many cases errors
from strconv.ParseUint are returned as is, meaning there is no context
telling which file we were reading. Similarly, errors from
fscommon.ParseKeyValue should be wrapped to add more context.
Same is true for scanner.Err().
One special case that repeats a few times is "malformed line: xxx".
Add and use a helper for that to simplify things.
OTOH, errors from fscommon.GetCgroup* do have enough context and there
is no need to wrap them.
Fix all the above.
While at it, add a missing scanner.Err() check.
[v2: use parseError not ParseError]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Kir Kolyshkin