p2p: decrease frameReadTimeout to 30s
p2p: decrease frameReadTimeout to 30s

This detects hanging connections sooner. We send a ping every 15s and
other implementation have similar limits.

maran/go-ethereum,maran/go-ethereum,maran/go-ethereum,maran/go-ethereum,maran/go-ethereum,maran/go-ethereum,maran/go-ethereum,maran/go-ethereum,maran/go-ethereum