CLI: Explicit api-path not encoded correctly

[olofhagsand]

If an api-path-fmt is manually given, the encoding of arguments was not properly RFC8040 encoded in some circumstances.
More specifically, with an api-path on the form: a/b=,%s
and an argument such as: 10/10
the resulting api-path is a/b=,10/10 where 10/10 is not encoded which it should.