Escape colons in DoctrineNamespaceCacheKey[<cache namespace>]

[Dadibom]

Using the redis cache driver, I want to be able to use doctrine: as my namespace, as this will turn doctrine into a folder thus keeping redis browsable. However, as the colon is not escaped, this key stops working: DoctrineNamespaceCacheKey[doctrine:]

[Ocramius]

@Dadibom can you report this on doctrine/cache please?

Also, not sure if this shouldn't simply be reported as redis issue...