(Info-find-node): Add 1 to the position read from the

(Info-find-node): Add 1 to the position read from the
tag table.  Don't fail if the node delimiter ^_ is the first
character in the file.
(Info-insert-dir): Don't fail when the node delimiter ^_ is the
first character in the file.
(Info-read-subfile): Likewise.
(Info-select-node): Likewise.
(Info-build-node-completions): Likewise.