Improve support of sysctl name seprators

Sysctl names can use dots or slashes as separator:

- if dots are used, dots and slashes are interchanged.
- if slashes are used, slashes and dots are left intact.

Separator in use is determined by firt ocurrence.

Reference: http://man7.org/linux/man-pages/man5/sysctl.d.5.html

Signed-off-by: Jaime Caamaño Ruiz <jcaamano@suse.com>

pkg/utils/sysctl/sysctl_suite_test.go

@@ -0,0 +1,13 @@
+package sysctl_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestSysctl(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Sysctl Suite")
+}