api.c: search_and_append_mnt_path() use strncpy()

api.c: search_and_append_mnt_path() use strncpy()

Fix copy into fixed size buffer warning, reported by Coverity tool:

CID 258279 (#1 of 1): Copy into fixed size buffer (STRING_OVERFLOW).
fixed_size_dest: You might overrun the 4096-character fixed-size string
mnt_point->path by copying path without checking the length.
10. parameter_as_source: Note: This defect has an elevated risk
because the source argument is a parameter of the current function.

fix this issue by using strnpy(), in place of strcpy().

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