ldap: handle more elegantly that python-ldap isn't installed when trying to use ldap

Don't fail with
  AttributeError: 'NoneType' object has no attribute 'SCOPE_SUBTREE'
in the log.

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fixes #807: Remove generic HTML title for repository groups

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fix unicode issues on logging in SCM middlewares

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added url quote in clone url. fixes issue #809

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fixed issues with importing non-ascii repo names

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tests docs

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