Won't be able to build swss_1.0.0_amd64.deb after run vs test cases

[zhenggen-xu]

Description

Steps to reproduce the issue:

1. Run vs tests as mentioned here:
   https://github.com/Azure/sonic-swss/blob/master/tests/README.md

2. trying to rebuild swss_1.0.0_amd64.deb by:
   make target/debs/swss_1.0.0_amd64.deb

hit error:
find: ./tests/log/log': Permission denied find: ./tests/log/log': Permission denied
find: `./tests/log/log': Permission denied
dh_autotools-dev_restoreconfig: find . -type f ( -name config.guess.dh-orig -o -name config.sub.dh-orig ) -delete returned exit code 1
debian/rules:22: recipe for target 'clean' failed
make[1]: *** [clean] Error 25

3, $ ls -lrt src/sonic-swss/tests/log
total 4
drwx------ 3 root root 4096 Nov 25 22:33 log

If I remove sonic-swss/tests/log manually by sudo, them it will be able to build again.

Describe the results you received:
won't build after run vs tests

Describe the results you expected:
should be able to build image successfully. Build system should ignore the log directory or the permission should be changed.

Additional information you deem important (e.g. issue happens only occasionally):

**Output of `show version`:**

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**Attach debug file `sudo generate_dump`:**

```
(paste your output here)
```