core: fix file not closed when exception in FS

modules/core/src/persistence.cpp

@@ -4525,6 +4525,7 @@ cvOpenFileStorage( const char* query, CvMemStorage* dststorage, int flags, const
         }
         catch (...)
         {
+            fs->is_opened = true;
             cvReleaseFileStorage( &fs );
             throw;
         }

modules/core/test/test_io.cpp

@@ -1352,7 +1352,7 @@ TEST(Core_InputOutput, FileStorage_free_file_after_exception)
     const std::string content = "%YAML:1.0\n cameraMatrix;:: !<tag:yaml.org,2002:opencv-matrix>\n";
 
     fstream testFile;
-    testFile.open(fileName, std::fstream::out);
+    testFile.open(fileName.c_str(), std::fstream::out);
     if(!testFile.is_open()) FAIL();
     testFile << content;
     testFile.close();
@@ -1360,9 +1360,10 @@ TEST(Core_InputOutput, FileStorage_free_file_after_exception)
     try
     {
         FileStorage fs(fileName, FileStorage::READ + FileStorage::FORMAT_YAML);
+        FAIL();
     }
     catch (const std::exception&)
     {
-        ASSERT_EQ(std::remove(fileName.c_str()), 0);
     }
+    ASSERT_EQ(std::remove(fileName.c_str()), 0);
 }