fix a couple of things with scripts

[vuillaut]

• unused import
• better path management
• an issue with main in r0 to dl2 + test

[codecov]

Codecov Report

Merging #341 into master will increase coverage by 0.08%.
The diff coverage is 27.27%.

@@            Coverage Diff             @@
##           master     #341      +/-   ##
==========================================
+ Coverage   43.59%   43.67%   +0.08%     
==========================================
  Files          69       69              
  Lines        4618     4623       +5     
==========================================
+ Hits         2013     2019       +6     
+ Misses       2605     2604       -1     

Impacted Files	Coverage Δ
lstchain/scripts/lstchain_dl1_to_dl2.py	0.00% <0.00%> (ø)
lstchain/scripts/lstchain_mc_dl1ab.py	0.00% <ø> (ø)
lstchain/scripts/lstchain_mc_r0_to_dl1.py	0.00% <0.00%> (ø)
lstchain/scripts/lstchain_mc_r0_to_dl2.py	0.00% <0.00%> (ø)
lstchain/scripts/tests/test_lstchain_scripts.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cc51d7e...fb1c467. Read the comment docs.