api: Fix clang warning

api: Fix clang warning

Fix the following warnings from clang by reducing the size passed to
strncat by 1 as recommended by clang.

	api.c:3727:22: warning: the value of the size argument in 'strncat' is
	too large, might lead to a buffer overflow [-Wstrncat-size]
	 3727 |         strncat(path, file, sizeof(path) - strlen(path));
	      |                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~
	api.c:3727:22: note: change the argument to be the free space in the
	destination buffer minus the terminating null byte
	 3727 |         strncat(path, file, sizeof(path) - strlen(path));
	      |                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~
	      |                             sizeof(path) - strlen(path) - 1

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>