clone: simplifying dest repo creation
since creating a repo raises an exception if the repo already
exists, there's no need to try to create one.
add some test for repo creation when the destination exists
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adding a
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8435f90966e4: a
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Thu Jan 01 00:00:01 1970 +0000: a
% annotate -n
0: a
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nobody: a
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nobody 0 8435f90966e4 Thu Jan 01 00:00:01 1970 +0000: a