Bug fixes and typo fixes

There were a couple bugs in the previous merge request made to add the lvc rates and pop codes into gstlal-ugly. This is a merge request to fix those bugs, as well as typos found in the codes.

• gstlal-ugly/bin/gstlal_lvc_rates_injection_dag: fixed the executable in the script from lvc_rates_injection_dag to gstlal_lvc_rates_injection_dag
• gstlal-ugly/bin/gstlal_lvc_rates_injections: fixed the executable in the script from lvc_rates_injection_dag to gstlal_lvc_rates_injection_dag
• gstlal-ugly/bin/gstlal_lvc_rates_injections: fix the description of option snr-threshold from sayng "Set the single detector snr threshold" and "default = 3.0" to "Set the network snr threshold" and "default = 5.0"
• gstlal-ugly/python/injection_generation_dag.py: remove from gstlal.dags.util import pipeline_dot_py_append_opts_hack and adjust the script
• gstlal-ugly/python/injection_utils.py: clean up for aesthetic reasons

added 2 commits

• 0892e754 - 1 commit from branch master
• 8bdab589 - Merge remote-tracking branch 'origin/master' into tom_mass_model

Compare with previous version

enabled an automatic merge when the pipeline for 8bdab589 succeeds

merged