rpc/net_info: change RemoteIP type from net.IP to String

Before:
"AAAAAAAAAAAAAP//rB8ktw=="
which is amino-encoded net.IP byte slice

After:
"192.0.2.1"

Fixes #3251

CHANGELOG_PENDING.md

@@ -23,3 +23,6 @@ Special thanks to external contributors on this release:
 ### BUG FIXES:
 - [consensus] \#3297 Flush WAL on stop to prevent data corruption during
   graceful shutdown
+- [rpc] \#3251 Fix /net_info#peers#remote_ip format. New format spec:
+  * dotted decimal ("192.0.2.1"), if ip is an IPv4 or IP4-mapped IPv6 address
+  * IPv6 ("2001:db8::1"), if ip is a valid IPv6 address

rpc/core/net.go

@@ -43,7 +43,8 @@ import (
 // }
 // ```
 func NetInfo() (*ctypes.ResultNetInfo, error) {
-	peers := []ctypes.Peer{}
+	out, in, _ := p2pPeers.NumPeers()
+	peers := make([]ctypes.Peer, 0, out+in)
 	for _, peer := range p2pPeers.Peers().List() {
 		nodeInfo, ok := peer.NodeInfo().(p2p.DefaultNodeInfo)
 		if !ok {
@@ -53,7 +54,7 @@ func NetInfo() (*ctypes.ResultNetInfo, error) {
 			NodeInfo:         nodeInfo,
 			IsOutbound:       peer.IsOutbound(),
 			ConnectionStatus: peer.Status(),
-			RemoteIP:         peer.RemoteIP(),
+			RemoteIP:         peer.RemoteIP().String(),
 		})
 	}
 	// TODO: Should we include PersistentPeers and Seeds in here?

rpc/core/types/responses.go

@@ -2,7 +2,6 @@ package core_types
 
 import (
 	"encoding/json"
-	"net"
 	"time"
 
 	abci "github.com/tendermint/tendermint/abci/types"
@@ -111,7 +110,7 @@ type Peer struct {
 	NodeInfo         p2p.DefaultNodeInfo  `json:"node_info"`
 	IsOutbound       bool                 `json:"is_outbound"`
 	ConnectionStatus p2p.ConnectionStatus `json:"connection_status"`
-	RemoteIP         net.IP               `json:"remote_ip"`
+	RemoteIP         string               `json:"remote_ip"`
 }
 
 // Validators for a height