unset keep handle open for test

Author: mlathara

test/src/storage_manager/test_posixfs.cc

@@ -156,6 +156,7 @@ TEST_CASE_METHOD(PosixFSTestFixture, "Test PosixFS file", "[file]") {
 
 TEST_CASE_METHOD(PosixFSTestFixture, "Test PosixFS read/write file", "[read-write]") {
   test_dir += "read_write";
+  unsetenv("TILEDB_KEEP_FILE_HANDLES_OPEN");
   CHECK_RC(fs.create_dir(test_dir), TILEDB_FS_OK);
   REQUIRE(fs.is_dir(test_dir));
   CHECK_RC(fs.write_to_file(test_dir+"/foo", "hello", 5), TILEDB_FS_OK);