Fix osquery version check

[javuto]

Fix osquery version check

Three bugs in the verify version-check path.

osqueryVersionCompare was not a SemVer comparison

It returned 1 on the first component where existing > required without first establishing that the higher-order components were equal, so 1.9.0 compared as newer than 2.0.0 — and 2.0.0 vs 1.9.0 returned 1 as well. The trailing res := 2 fallthrough also meant 1.2 vs 1.2.0 reported "required is higher" instead of equal.

Now compares component by component after zero-padding, returning at the first difference, and 0 when all components are equal.

getOsqueryVersion could panic

Guarded len(splitted) < 2 but indexed splitted[2] — two-field output panicked with index out of range [2] with length 2. It only worked because osqueryd -version happens to print three fields.

Guard is now len(fields) < 3. Parsing moved to parseOsqueryVersion so the case is testable without executing osqueryd; uses strings.Fields, which also drops the separate TrimSpace and tolerates repeated spaces.

An unknown version reported as valid

verify checked > 1, so the -1 error sentinel fell through to logging "osquery version is valid". Now a switch: 2 → too low, -1 → "unknown osquery version", otherwise valid.

Tests

Table-driven: 15 cases for the comparison (both directions of 1.9.0/2.0.0, equal, mismatched component counts, 5.10.0 vs 5.9.0 to pin numeric-not-lexical ordering, both error sentinels) and 7 for the parse (three-, two-, one-field, empty). Confirmed failing against the pre-fix code.

go test ./cmd/osctrld/ -race — 85 pass. golangci-lint run ./... — 0 issues.