Travis CI UT failure

[ralf0131]

• I have searched the issues of this repository and believe that this is not a duplicate.
• I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

• Dubbo version: 2.7.0
• Operating System version: Linux
• Java version: Java 11

Steps to reproduce this issue

Travis CI failed with the following log
https://api.travis-ci.org/v3/job/485054109/log.txt

Expected Result

CI pass.

Actual Result

CI Failure.

[�[1;34mINFO�[m] Running org.apache.dubbo.registry.redis.�[1mRedisRegistryTest�[m
log4j:WARN No appenders could be found for logger (org.apache.dubbo.common.logger.LoggerFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
[�[1;31mERROR�[m] �[1;31mTests �[0;1mrun: �[0;1m5�[m, Failures: 0, �[1;31mErrors: �[0;1;31m1�[m, Skipped: 0, Time elapsed: 1.202 s�[1;31m <<< FAILURE!�[m - in org.apache.dubbo.registry.redis.�[1mRedisRegistryTest�[m
[�[1;31mERROR�[m] testAnyHost  Time elapsed: 0.201 s  <<< ERROR!
redis.embedded.exceptions.EmbeddedRedisException: Failed to start Redis instance
	at org.apache.dubbo.registry.redis.RedisRegistryTest.setUp(RedisRegistryTest.java:50)
Caused by: java.io.IOException: Cannot run program "/tmp/1548641223184-0/redis-server-2.8.19" (in directory "/tmp/1548641223184-0"): error=26, Text file busy
	at org.apache.dubbo.registry.redis.RedisRegistryTest.setUp(RedisRegistryTest.java:50)
Caused by: java.io.IOException: error=26, Text file busy
	at org.apache.dubbo.registry.redis.RedisRegistryTest.setUp(RedisRegistryTest.java:50)

[�[1;34mINFO�[m] 
[�[1;34mINFO�[m] Results:
[�[1;34mINFO�[m] 
[�[1;31mERROR�[m] �[1;31mErrors: �[m
[�[1;31mERROR�[m] �[1;31m  RedisRegistryTest.setUp:50 » EmbeddedRedis Failed to start Redis instance�[m
[�[1;34mINFO�[m] 
[�[1;31mERROR�[m] �[1;31mTests run: 5, Failures: 0, Errors: 1, Skipped: 0�[m

[biyuhao]

kstyrc/embedded-redis#85

[ralf0131]

@biyuhao Would you like to help to fix it?

[biyuhao]

Yes, it's hard to reproduce in my environment.
I'm willing to give it a try.