Internal: delete unused common.VersionLessThan()

The function is a leftover from the image definitions split and it is
not used. Moreover, the `images` copy of it is being reimplemented by
[1]. It is better to remove this copy to prevent any unintended use of
it or confusion.

[1] https://github.com/osbuild/images/pull/195

Signed-off-by: Tomáš Hozza <thozza@redhat.com>

internal/common/distro.go

@@ -51,33 +51,3 @@ func readOSRelease(r io.Reader) (map[string]string, error) {
 
 	return osrelease, nil
 }
-
-// Returns true if the version represented by the first argument is
-// semantically older than the second.
-// Meant to be used for comparing distro versions for differences between minor
-// releases.
-// Evaluates to false if a and b are equal.
-// Assumes any missing components are 0, so 8 < 8.1.
-func VersionLessThan(a, b string) bool {
-	aParts := strings.Split(a, ".")
-	bParts := strings.Split(b, ".")
-
-	// pad shortest argument with zeroes
-	for len(aParts) < len(bParts) {
-		aParts = append(aParts, "0")
-	}
-	for len(bParts) < len(aParts) {
-		bParts = append(bParts, "0")
-	}
-
-	for idx := 0; idx < len(aParts); idx++ {
-		if aParts[idx] < bParts[idx] {
-			return true
-		} else if aParts[idx] > bParts[idx] {
-			return false
-		}
-	}
-
-	// equal
-	return false
-}