Remove some more pegasus-related code in lalapps/inspiral.py

+### Description

@duncanmmacleod It looks like we missed this in !1694 (merged). Using this code against the current glue.pipeline fails as the methods that are called no longer exist.

.... There is an issue here that the current release of this file (without !1694 (merged)) is incompatible with the latest release of glue (which has pegasus stuff removed). This causes sbank_pipe failures if using the latest versions of these codes.

API Changes and Justification

No API changes.

Backwards Compatible Changes

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• This change adds new API calls

Backwards Incompatible Changes

• This change modifies an existing API
• This change removes an existing API

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