app/test: fix misplaced braces in strncmp

app/test: fix misplaced braces in strncmp

One occurrence call to strncmp had the closing brace in the wrong
place. Changing this form:
	if (strncmp(X, Y, sizeof(X) != 0))
which does a comparison of length 1, to
	if (strncmp(X, Y, sizeof(X)) != 0)
which does the correct length comparison and then compares the result
to zero in the "if" part.

Seen with clang-3.5:
  "error: size argument in 'strncmp' call is a comparison"

This patch is similar to 261386248 but it looks that one occurrence
was forgotten.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>