Move Matches() file path matching function into pkg/fileutils

This is the second of two steps to break the archive package's
dependence on utils so that archive may be moved into pkg. `Matches()`
is also a good candidate pkg in that it is small, concise, and not
specific to docker internals

Signed-off-by: Rafe Colton <rafael.colton@gmail.com>

fileutils/fileutils.go

@@ -0,0 +1,26 @@
+package fileutils
+
+import (
+	"github.com/docker/docker/pkg/log"
+	"path/filepath"
+)
+
+// Matches returns true if relFilePath matches any of the patterns
+func Matches(relFilePath string, patterns []string) (bool, error) {
+	for _, exclude := range patterns {
+		matched, err := filepath.Match(exclude, relFilePath)
+		if err != nil {
+			log.Errorf("Error matching: %s (pattern: %s)", relFilePath, exclude)
+			return false, err
+		}
+		if matched {
+			if filepath.Clean(relFilePath) == "." {
+				log.Errorf("Can't exclude whole path, excluding pattern: %s", exclude)
+				continue
+			}
+			log.Debugf("Skipping excluded path: %s", relFilePath)
+			return true, nil
+		}
+	}
+	return false, nil
+}