Request for Review: Execute the build logger with the help of a shell if the x permission is not set

[Magnus Ihse Bursie]

In the build-infra hg repo, we allowed execute permission to be set on 
files, including common/bin/logger.sh, which is called by the Makefile.

The official hg repos strip this bit, so when integrating to the build 
forest, this was lost, causing the Makefile to fail since it can't 
execute logger.sh.

This fix looks if the x permission is there, otherwise it calls 
logger.sh using the shell.

Webrev:
http://cr.openjdk.java.net/~ihse/logger.sh-missing-x-permission/webrev.00/

/Magnus