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
--
A dir/b.o
? a.c
? a.o
? dir/c.o
? syntax
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abort: .hgignore: invalid pattern (relre): *.o
--
A dir/b.o
? .hgignore
? a.c
? syntax
--
.hgignore: ignoring invalid syntax 'invalid'
A dir/b.o
? .hgignore
? a.c
? a.o
? dir/c.o
? syntax
--
A dir/b.o
? .hgignore
? a.c
? syntax
--
A dir/b.o
? .hgignore
? a.c
? a.o
? dir/c.o
--
A dir/b.o
--
A b.o