quote: Fix returning out of string pointer
quote: Fix returning out of string pointer

In case if string is a single grave accent we
return the pointer to uninitialized space.

http://bugzilla.nasm.us/show_bug.cgi?id=3392292

Signed-off-by: Cyrill Gorcunov <7a1ea01eee6961eb1e372e3508c2670446d086f4@gmail.com>

techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm