Remove spurious * in docstrings.

Remove spurious * in docstrings.
(snmp-rfc1155-types, snmp-rfc1213-types, snmp-rfc1902-types)
(snmp-rfc1903-types, snmp-rfc1155-access, snmp-rfc1902-access)
(snmp-rfc1212-status, snmp-rfc1902-status): Remove list wrappers now
that completion accepts lists of strings.
(snmp-mode-syntax-table): Move initialization into declaration.
(snmp-mode-map): Likewise and remove \t binding.
(snmp-common-mode): Set tab-always-indent according to snmp-t-a-i.
(snmp-indent-line, snmp-mode-imenu-create-index): Remove unused var.
(snmp-indent-command): Remove.