fs_mgr: liblp test: give ownership of environment to gtest

From gtest doc:
Note that googletest takes ownership of the registered environment objects. Therefore do not delete them by yourself.

Test: run it
Change-Id: I275884ddd63a17097c3ea4d9d6bb2b5291dc8c90
diff --git a/fs_mgr/liblp/builder_test.cpp b/fs_mgr/liblp/builder_test.cpp
index 34c68d4..fd16e90 100644
--- a/fs_mgr/liblp/builder_test.cpp
+++ b/fs_mgr/liblp/builder_test.cpp
@@ -31,8 +31,7 @@
 };
 
 int main(int argc, char** argv) {
-    std::unique_ptr<Environment> env(new Environment);
-    ::testing::AddGlobalTestEnvironment(env.get());
+    ::testing::AddGlobalTestEnvironment(new Environment);
     ::testing::InitGoogleTest(&argc, argv);
     return RUN_ALL_TESTS();
 }