[Bridge] [Propel] minor improvements to the Propel bridge.
minor #13063 [2.3] [Bridge] [Propel] minor improvements to the Propel bridge. (hhamon)

This PR was merged into the 2.3 branch.

Discussion
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[2.3] [Bridge] [Propel] minor improvements to the Propel bridge.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | ~
| License       | MIT
| Doc PR        | ~

Commits
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6d9d460 [Bridge] [Propel] minor improvements to the Propel bridge.
Merge branch '2.3' into 2.5

* 2.3:
  [Bridge] [Propel] minor improvements to the Propel bridge.

Conflicts:
	src/Symfony/Bridge/Propel1/Tests/Fixtures/Column.php
Merge branch '2.5' into 2.6

* 2.5:
  [Bridge] [Propel] minor improvements to the Propel bridge.
  [FrameworkBundle] Allow custom services for validator mapping cache.
Merge branch '2.6' into 2.7

* 2.6:
  [Bridge] [Propel] minor improvements to the Propel bridge.
  [FrameworkBundle] Allow custom services for validator mapping cache.