Add one more skip level due to breaking change in github.com/sirupsen…

…/logrus

Apparently due to this [merge request](sirupsen/logrus#863)
another level to stacktrace was introduced. So if we intend to skip it
by default we have to increase default number of skips in our
configuration.

sentry.go

@@ -113,7 +113,7 @@ func NewWithClientSentryHook(client *raven.Client, levels []logrus.Level) (*Sent
 		StacktraceConfiguration: StackTraceConfiguration{
 			Enable:            false,
 			Level:             logrus.ErrorLevel,
-			Skip:              5,
+			Skip:              6,
 			Context:           0,
 			InAppPrefixes:     nil,
 			SendExceptionType: true,