test: use fs namespace in dbwrapper unicodepath test

Author: fanquake

src/test/dbwrapper_tests.cpp

@@ -399,15 +399,15 @@ BOOST_AUTO_TEST_CASE(iterator_string_ordering)
 
 BOOST_AUTO_TEST_CASE(unicodepath)
 {
-    // Attempt to create a database with a utf8 character in the path.
+    // Attempt to create a database with a UTF8 character in the path.
     // On Windows this test will fail if the directory is created using
-    // the ANSI CreateDirectoryA  call and the code page isn't UTF8.
-    // It will succeed if the created with  CreateDirectoryW.
+    // the ANSI CreateDirectoryA call and the code page isn't UTF8.
+    // It will succeed if created with CreateDirectoryW.
     fs::path ph = GetDataDir() / "test_runner_₿_🏃_20191128_104644";
     CDBWrapper dbw(ph, (1 << 20));
 
     fs::path lockPath = ph / "LOCK";
-    BOOST_CHECK(boost::filesystem::exists(lockPath));
+    BOOST_CHECK(fs::exists(lockPath));
 }