Fix quitting bug when buffers are frozen

Fix quitting bug when buffers are frozen

Problem noted by Eli Zaretskii in:
http://lists.gnu.org/archive/html/emacs-devel/2017-01/msg00721.html
This patch also fixes some other issues in that report.
* src/lisp.h (incr_rarely_quit): Remove.
All callers changed to use rarely_quit directly.
* src/search.c (freeze_buffer_relocation)
(thaw_buffer_relocation): New functions.
(looking_at_1, fast_looking_at, search_buffer):
Use them to fix bug when quitting when buffers are frozen.
* src/sysdep.c (emacs_intr_read): Rename from emacs_nointr_read.
All uses changed.