Update CHANGELOG.md

Clarified the description of the 7.3.1 UAA token format changes to hopefully be less ambiguous

CHANGELOG.md

@@ -147,22 +147,21 @@ We increased the tolerance of the acceptance suite by capturing additional test
 ## 7.3.1
 
 ### Bug Fixes
+- Before version 7.0, om had been using UAA's default `token_format`
+ (`jwt`), and the optional `token_format` parameter went unused.
 
-- Way back in 7.0, incidental to switching to the uaa-go library,
+ However in version 7.0, incidental to switching to the uaa-go library,
  om started requesting `opaque` access tokens from UAA
- to access Ops Manager.
- The change wasn't deliberate, and didn't even make the release notes.
+ to access Ops Manager instead of `jwt` ones. This wasn't
+ deliberate, and didn't even make the release notes.
 
  These implicitly revocable tokens may be contributing to
  a hard-to-repro issue around parallel access
  in a customer environment.
 
- Before the change, the optional `token_format` parameter went unused,
- and UAA's default `token_format`, `jwt`, was used.
-
  This release explicitly requests `jwt` access tokens,
- restoring the previous behavior,
- and potentially addressing said parallel-access issue.
+ restoring the pre-7.0 behavior and potentially addressing said
+ parallel-access issue.
 
 ## 7.3.0
 ### Features