When installing a plugin from a local binary, Packer builds the name of
the plugin from the results of the `describe' command.
Depending on how the plugin is built, the version reported may or may
not contain a leading `v', which was not taken into account beforehand
and the leading `v' was always injected in the path.
This caused plugins that report a leading `v' in their version to
be installed with two v's in their path, making them impossible to load.
Therefore to fix this issue, we count on the version library to print
out a version without the leading v, and we inject that in the resulting
path.
Lucas Bajolet
3f721ff03e