Update grok version (#2662)

Godeps

@@ -49,7 +49,7 @@ github.com/shirou/gopsutil dfbb3e40da8d6fcd1aa0d87003e965fe0ca745ea
 github.com/soniah/gosnmp 5ad50dc75ab389f8a1c9f8a67d3a1cd85f67ed15
 github.com/streadway/amqp 63795daa9a446c920826655f26ba31c81c860fd6
 github.com/stretchr/testify 4d4bfba8f1d1027c4fdbe371823030df51419987
-github.com/vjeantet/grok 83bfdfdfd1a8146795b28e547a8e3c8b28a466c2
+github.com/vjeantet/grok d73e972b60935c7fec0b4ffbc904ed39ecaf7efe
 github.com/wvanbergen/kafka bc265fedb9ff5b5c5d3c0fdcef4a819b3523d3ee
 github.com/wvanbergen/kazoo-go 968957352185472eacb69215fa3dbfcfdbac1096
 github.com/yuin/gopher-lua 66c871e454fcf10251c61bf8eff02d0978cae75a

plugins/inputs/logparser/grok/grok_test.go

@@ -687,3 +687,23 @@ func TestTsModder_Rollover(t *testing.T) {
 	}
 	assert.Equal(t, reftime.Add(time.Nanosecond*1000), modt)
 }
+
+func TestShortPatternRegression(t *testing.T) {
+	p := &Parser{
+		Patterns: []string{"%{TS_UNIX:timestamp:ts-unix} %{NUMBER:value:int}"},
+		CustomPatterns: `
+		  TS_UNIX %{DAY} %{MONTH} %{MONTHDAY} %{HOUR}:%{MINUTE}:%{SECOND} %{TZ} %{YEAR}
+		`,
+	}
+	require.NoError(t, p.Compile())
+
+	metric, err := p.ParseLine(`Wed Apr 12 13:10:34 PST 2017 42`)
+	require.NoError(t, err)
+	require.NotNil(t, metric)
+
+	require.Equal(t,
+		map[string]interface{}{
+			"value": int64(42),
+		},
+		metric.Fields())
+}