opam: Avoid unnecessary raise instructions
This simplifies the logic behind the parsing of the opam_read function to avoid
raising outside of the opam_read call.
Related to T3425
Test Plan
tox
Migrated from D6009 (view on Phabricator)
This simplifies the logic behind the parsing of the opam_read function to avoid
raising outside of the opam_read call.
Related to T3425
tox
Migrated from D6009 (view on Phabricator)