VOL-1925, VOL-1882 affinity-router.go unit tests; fix varint skip issue

Change-Id: I0baba72351bbf026985761bf217aecfd288ccdbd
diff --git a/afrouter/afrouter/affinity-router.go b/afrouter/afrouter/affinity-router.go
index 7a3168e..7a94f7b 100644
--- a/afrouter/afrouter/affinity-router.go
+++ b/afrouter/afrouter/affinity-router.go
@@ -202,10 +202,14 @@
 func (ar AffinityRouter) skipField(data *[]byte, idx *int) error {
 	switch (*data)[*idx] & 3 {
 	case 0: // Varint
+		// skip the field number/type
 		*idx++
+		// if the msb is set, then more bytes to follow
 		for (*data)[*idx] >= 128 {
 			*idx++
 		}
+		// the last byte doesn't have the msb set
+		*idx++
 	case 1: // 64 bit
 		*idx += 9
 	case 2: // Length delimited