cmd/log-parser: Add containerID and sandboxID to standard log entry

[jodh-intel]

Extract the container ID from the structured logs and add it to the
standard LogEntry type. This will allow (most of) the log entries to
be associated with individual containers, which will make debugging and
analysis easier.

Also, enhance some of the errors that are returned to make locating the issue
in the log file easier.

Fixes #453.

Signed-off-by: James O. D. Hunt james.o.hunt@intel.com

[grahamwhaley]

lgtm
Hopefully I'll get to try this soon as well.

[chavafg]

lgtm

[chavafg]

some CI errors:

cmd/log-parser/agent_test.go:174:3:warning: unused struct field github.com/kata-containers/tests/cmd/log-parser.testData.expectContainerField (structcheck)
cmd/log-parser/agent_test.go:173:3:warning: unused struct field github.com/kata-containers/tests/cmd/log-parser.testData.le (structcheck)
cmd/log-parser/agent_test.go:172:7:warning: type testData is unused (U1000) (unused)
Build step 'Execute shell' marked build as failure

[jodh-intel]

Branch updated.

[jodh-intel]

Branch updated to resolve merge conflict.

[jodh-intel]

Branch updated to also pick out the sandboxID. Note that we don't actually need to wait for the PRs on #474 to land before this PR lands as containerID and sandboxID are not mandatory fields (they can't be).

[devimc]

lgtm