phosphor: net-snmp: move to recipes-protocols

No functional change, but move net-snmp from recipes-connectivity to
recipes-protocols to match the hierarchy of the meta-networking layer.

Change-Id: If62b8df431c69706718041c1c9769167f57d642c
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/recipes.txt b/recipes.txt
index ccd19b2..834b3bf 100644
--- a/recipes.txt
+++ b/recipes.txt
@@ -5,3 +5,4 @@
                        core. May be needed for full tool functionality or LSB compliance.
 recipes-kernel       - The kernel and generic applications/libraries with strong kernel dependencies
 recipes-phosphor     - Phosphor OpenBMC applications and configuration
+recipes-protocols    - bbappends from recipes-protocols in the meta-networking layer