gcc 4.9.2 emits missing braces warning #932

src/modules/schnorrsig/tests_impl.h: In function ‘test_schnorrsig_api’:
src/modules/schnorrsig/tests_impl.h:106:5: warning: missing braces around initializer [-Wmissing-braces]
     secp256k1_keypair invalid_keypair = { 0 };