If spdk_json_number_to_int32() works correctly, it will initialize the
value of i32, but since this is a unit test, we should make sure i32 is
initialized to catch bugs.
Fixes a clang warning during scan-build.
Change-Id: Iecf0531d2992acf584b10e2de5f8c53553a9f3b6
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>