activate scripts written by isisVarInit.py should always have absolute paths

[rbeyer]

ISIS version(s) affected: 4.all

Description
If you mistakenly provide a relative path to any of the optional arguments to isisVarInit.py, those relative paths will be written into the generated activation scripts. This results in unexpected behavior, as the various ISIS environment variables should be fully-resolved, absolute paths, not relative ones.

How to reproduce

cd $HOME
python $CONDA_PREFIX/scripts/isisVarInit.py -d foo

The resulting activation scripts will have ISISDATA set to just the bare value of foo instead of /absolute/path/to/$HOME/foo.

Possible Solution
Fully resolve the provided paths.