b2f23c41538eaadd71c373ada75dd3a982eeb8bf [RPC] Remove getinfo deprecation warning (John Newbery)
Pull request description:
`getinfo` was removed in V0.16. A removal warning message was left in place to tell users that the method had been removed. We can remove that entirely in V0.18.
Tree-SHA512: bf93fbcf57a9be480438dcbdcab2dfd69ce277218b10628776975b093b3ffd2caa1751e0fb4cb0245443c81465693e2b8750e96d3e38632a78bae5ffa04f9212
Backport of Core PR13891