Replace try-with-resources with try and finally so that we don't have desugaring issues (#626)

* update rc

* address comments

* fix file not found exception

* no if needed

* gJF

Author: VinayGuthal

firebase-config/src/main/java/com/google/firebase/remoteconfig/internal/ConfigStorageClient.java

@@ -76,8 +76,11 @@ private ConfigStorageClient(Context context, String fileName) {
    */
   public synchronized Void write(ConfigContainer container) throws IOException {
     // TODO(issues/262): Consider using the AtomicFile class instead.
-    try (FileOutputStream outputStream = context.openFileOutput(fileName, Context.MODE_PRIVATE)) {
+    FileOutputStream outputStream = context.openFileOutput(fileName, Context.MODE_PRIVATE);
+    try {
       outputStream.write(container.toString().getBytes(JSON_STRING_ENCODING));
+    } finally {
+      outputStream.close();
     }
     return null;
   }
@@ -90,7 +93,13 @@ public synchronized Void write(ConfigContainer container) throws IOException {
    */
   @Nullable
   public synchronized ConfigContainer read() throws IOException {
-    try (FileInputStream fileInputStream = context.openFileInput(fileName)) {
+    try {
+      context.openFileInput(fileName);
+    } catch (FileNotFoundException e) {
+      return null;
+    }
+    FileInputStream fileInputStream = context.openFileInput(fileName);
+    try {
       byte[] bytes = new byte[fileInputStream.available()];
       fileInputStream.read(bytes, 0, bytes.length);
       String containerJsonString = new String(bytes, JSON_STRING_ENCODING);
@@ -100,6 +109,8 @@ public synchronized ConfigContainer read() throws IOException {
     } catch (JSONException | FileNotFoundException e) {
       // File might not have been written to yet, so this not an irrecoverable error.
       return null;
+    } finally {
+      fileInputStream.close();
     }
   }