Script_validator expects both an init_script and a compare_script, documentation conflicts with that statement.

[BoySanic]

Describe the bug
On the wiki page for ValidationSimple (https://boinc.berkeley.edu/trac/wiki/ValidationSimple#Usingscriptinglanguages) it states the following in the case that you are using Script_Validator:

"For applications that don't use replication, the compare script need not be given. For applications that don't need output file syntax checking, the init script need not be given."

The trouble with this is that the code contradicts this statement.

https://github.com/BOINC/boinc/blob/master/sched/script_validator.cpp#L79

For our project (Minecraft@Home), we didn't feel we needed a syntax script for the results we were getting out of the client. As a workaround, we created a small script that simply exits with 0 in order to appease script_validator's requirements.

Steps To Reproduce

1. Omit the --init_script or --compare_script parameters when running script_validator (only one of the two)
2. Result from command-line "init_script and/or compare_script names are missing from command line"

Expected behavior
Either the documentation should be updated to reflect script_validator requiring both scripts, or the program should be updated to only require one of the two scripts at any given time.