MINOR: Double quote `CLASSPATH` to prevent shell glob expansion. (#8191)
MINOR: Double quote `CLASSPATH` to prevent shell glob expansion. (#8191)

In the event that `CLASSPATH` does not have an ending ":", the shell
can expand the CLASSPATH globs to be space-separated list of paths/jars,
which is not how the JVM CLI accepts arguments to -cp switch. So
double quote the variable to prevent pattern expansion, and pass the
glob pattern directly to the JVM.

Reviewers: Ismael Juma <0794a5c7e497910d682bf2c54c66cc30760c0221@juma.me.uk>
guozhangwang/kafka,Chasego/kafka,TiVo/kafka,apache/kafka,lindong28/kafka,lindong28/kafka,guozhangwang/kafka,Chasego/kafka,Chasego/kafka,apache/kafka,Chasego/kafka,guozhangwang/kafka,TiVo/kafka,sslavic/kafka,TiVo/kafka,lindong28/kafka,sslavic/kafka,apache/kafka,apache/kafka,guozhangwang/kafka,TiVo/kafka,sslavic/kafka,lindong28/kafka,sslavic/kafka