Make it possible to quote names in autofs maps using double quotes.

Note that this is a workaround, not a proper solution.  If you know
lex well, and want to help - please let me know, I'll explain how it
should work.

PR:		192968
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Revert r271159, Mis-patched the tree.

Pointed out by:	kib