Make job output files private by default.

Job output files are created by SGE with permissions 644 by default.
There has been concern that these files may contain passwords in stack
traces.

With this change, if job output files do not exist, they are
pre-created with permissions 600 for user accounts and 660 for tool
accounts.  SGE will just append to these files and not change the
permissions.

To fine-tune, users may supply the option "-umask UMASK" which will
override the default umask.  UMASK is interpreted as octal,
i. e. "-umask 022" does what one would expect.

This fixes bug #48818.

Bug: 48818
Change-Id: I94a2bd4af699d2d0c19cc429a56b932381510cf9
Merge "Make job output files private by default."