handle sync cancelling

Signed-off-by: parneet-guraya <gurayaparneet@gmail.com>

app/src/main/java/com/owncloud/android/ui/preview/PreviewImageFragment.java

@@ -412,6 +412,8 @@ public class PreviewImageFragment extends FileFragment implements Injectable {
             seeDetails();
         } else if (itemId == R.id.action_download_file || itemId == R.id.action_sync_file) {
             containerActivity.getFileOperationsHelper().syncFile(getFile());
+        }else if(itemId == R.id.action_cancel_sync){
+            containerActivity.getFileOperationsHelper().cancelTransference(getFile());
         } else if (itemId == R.id.action_set_as_wallpaper) {
             containerActivity.getFileOperationsHelper().setPictureAs(getFile(), getImageView());
         } else if (itemId == R.id.action_export_file) {

app/src/main/java/com/owncloud/android/ui/preview/PreviewMediaFragment.java

@@ -450,6 +450,8 @@ public class PreviewMediaFragment extends FileFragment implements OnTouchListene
             seeDetails();
         } else if (itemId == R.id.action_sync_file) {
             containerActivity.getFileOperationsHelper().syncFile(getFile());
+        } else if (itemId == R.id.action_cancel_sync) {
+            containerActivity.getFileOperationsHelper().cancelTransference(getFile());
         } else if (itemId == R.id.action_stream_media) {
             containerActivity.getFileOperationsHelper().streamMediaFile(getFile());
         } else if (itemId == R.id.action_export_file) {

app/src/main/java/com/owncloud/android/ui/preview/PreviewTextFileFragment.java

@@ -330,6 +330,8 @@ public class PreviewTextFileFragment extends PreviewTextFragment {
             seeDetails();
         } else if (itemId == R.id.action_sync_file) {
             containerActivity.getFileOperationsHelper().syncFile(getFile());
+        } else if(itemId == R.id.action_cancel_sync){
+            containerActivity.getFileOperationsHelper().cancelTransference(getFile());
         } else if (itemId == R.id.action_edit) {
             containerActivity.getFileOperationsHelper().openFileWithTextEditor(getFile(), getContext());
         }