Propagate RelaxedConversionService

Prior to this commit, the internal BeanWrapper used by the
RelaxedDataBinder was not using any conversion service at all. This
commit makes sure to propagate the one that has been configured
internally.

Also a dummy call to a [foo] key seems to have been left and has
been removed. This allows to support Enum as map key.

Fixes gh-1242
Export SPRING_HOME for commands to consume if needed