collector/cpu: s/cpu_ticks*/cpu_nsec* for solaris (#2963)

Replace all cpu_ticks_* with cpu_nsec_*, since the former was off my a
magnitude of 10e6, and showed incorrect values for
node_cpu_seconds_total.

Fixes: #1837

Signed-off-by: Pranshu Srivastava <rexagod@gmail.com>

collector/cpu_solaris.go

@@ -60,17 +60,17 @@ func (c *cpuCollector) Update(ch chan<- prometheus.Metric) error {
 		}
 
 		for k, v := range map[string]string{
-			"idle":   "cpu_ticks_idle",
-			"kernel": "cpu_ticks_kernel",
-			"user":   "cpu_ticks_user",
-			"wait":   "cpu_ticks_wait",
+			"idle":   "cpu_nsec_idle",
+			"kernel": "cpu_nsec_kernel",
+			"user":   "cpu_nsec_user",
+			"wait":   "cpu_nsec_wait",
 		} {
 			kstatValue, err := ksCPU.GetNamed(v)
 			if err != nil {
 				return err
 			}
 
-			ch <- c.cpu.mustNewConstMetric(float64(kstatValue.UintVal), strconv.Itoa(cpu), k)
+			ch <- c.cpu.mustNewConstMetric(float64(kstatValue.UintVal)/1e9, strconv.Itoa(cpu), k)
 		}
 	}
 	return nil