lalapps_path2cache fails on unparseable files

[astroclark]

The ile_pre.sh script creates a local frame cache file on the worker node when running as a +PreCmd on the OSG. If the directory piped to lalapps_path2cache contains an unparseable file (something like test.cache, instead of something like ---.gwf`, say..), valid cache file creation can fail.

Unfortunately, it can be hard to identify this failure as we don't see any stdout from the PreCmd (TODO: find out how to make that appear).

Suggestions:

1. Avoid putting anything other than frame files in the frames directory when setting up runs
2. Try adding --force to the call to lalapps_path2cache (see below)
3. Remove the -e from the header in the bash script. I thought this would be a good thing to have, orginally, since it causes the script to exit on failure, rather than going to the next command. It does not, however, stop the main job from running and it can even obscure further failures / debugging info.

Forcing lalapps_path2cache

[jclark@ldas-osg] $ lalapps_path2cache -h
Usage: lalapps_path2cache [options]
<snip>
  -f, --force           Ignore errors.  Unparseable file names are removed
                        from the output.  This has no effect if --include-all
                        is given.

Adding this option would probably improve robustness beyond just "being careful" not to put unwanted things in the frames dir.