Fixing the data-loss issue described in issue #230

[leonliao]

Fix the issue #230, non-blob keys are dropped by compaction_filter incorrectly, resulting in data loss.

Description

• Provided a patch
• Updated theCMakeLists.txt to apply the patch.

Motivation and Context

https://github.com/Tencent/Tendis/issues/230

How Has This Been Tested?

• Building Tendis
• Test with the steps in https://github.com/Tencent/Tendis/issues/230, and the data loss is gone.

Types of Changes

• [X] Bug fix (non-breaking change that fixes an issue)
• [ ] New feature (non-breaking change that adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [X] Code follows the code style of this project.
• [] Change requires a change to the documentation.
• [] I have updated the documentation accordingly.