logging: fix build failures in the tests

Summary: gcc-5.x does not allow brace elision in these std::array initializer lists.

Reviewed By: yfeldblum, mnv104

Differential Revision: D7923970

fbshipit-source-id: 807f2e0d376c9ac4f4f6988fb811590531b6334d

folly/logging/test/PrintfTest.cpp

@@ -109,7 +109,7 @@ TEST(PrintfTest, printfStyleMacros) {
   messages.clear();
 
   // more complex conditional expressions
-  std::array<bool, 2> conds = {false, true};
+  std::array<bool, 2> conds = {{false, true}};
   for (unsigned i = 0; i < conds.size(); i++) {
     for (unsigned j = 0; j < conds.size(); j++) {
       argumentEvaluated = false;

folly/logging/test/XlogTest.cpp

@@ -80,7 +80,7 @@ TEST_F(XlogTest, xlogIf) {
   messages.clear();
 
   // more complex conditional expressions
-  std::array<bool, 2> conds = {false, true};
+  std::array<bool, 2> conds = {{false, true}};
   for (unsigned i = 0; i < conds.size(); i++) {
     for (unsigned j = 0; j < conds.size(); j++) {
       XLOG_IF(DBG1, conds[i] && conds[j], "testing conditional");