[binutils-gdb] Fix build with GCC 8: strncpy ->strcpy

[sergiodj+buildbot at sergiodj dot net]

*** TEST RESULTS FOR COMMIT a9f26f609e3a1b6ae3aab300b55442e0a81e2bce ***

Author: Yao Qi <yao.qi@linaro.org>
Branch: master
Commit: a9f26f609e3a1b6ae3aab300b55442e0a81e2bce

Fix build with GCC 8: strncpy ->strcpy

Recent gcc 8 trunk emits the warning below,

../../binutils-gdb/gdb/python/py-gdb-readline.c:79:15: error: char* strncpy(char*, const char*, size_t) output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation]
       strncpy (q, p, n);
       ~~~~~~~~^~~~~~~~~
../../binutils-gdb/gdb/python/py-gdb-readline.c:73:14: note: length computed here
   n = strlen (p);
       ~~~~~~~^~~

gdb:

2017-11-22  Yao Qi  <yao.qi@linaro.org>

	* python/py-gdb-readline.c (gdbpy_readline_wrapper): Use strcpy.