RFC : pear metadata location.

Hi,

pear/pecl stores its metadata under "installdir" / "php_dir"

	.channels
	.depdb
	.filemap
	.registry

Under linux, according to FHS, this metadata should not be in this location.

Goal : allow to use different location, such as:

/usr/share/pear for php file installation (in the PHP include_path)
/var/lib/pear   for the metadata


Proposal :
Create a new configuration option "metadata_dir" which allow to
explicitly set this location. Of course, default value will be the same
as actually.


I will prefer some feedback before working on this change an submitting
a pull request on github.


Regards,
Remi.