Revert "net: ipv4: current group_info should be put after using."

This reverts commit 3931499bd4f86a366ebdb19d8b488982cc1f7e6f.
Revert "ping: prevent NULL pointer dereference on write to msg_name"

This reverts commit ed8d197fd73105194991c3e1a3b2739f4638c144.
Revert "ping: always initialize ->sin6_scope_id and ->sin6_flowinfo"

This reverts commit 6731de841528ed0571d17b91212ce9a00fb8d537.
Revert "net: ipv6: Add IPv6 support to the ping socket."

This reverts commit f451cf01444c6ada5baad0d9ad5b705b63b678ea.