phosphor: drop meta-webserver from sample conf

There aren't any dependencies in meta-phosphor on anything in
meta-webserver, so drop meta-webserver from the sample configuration.

(From meta-phosphor rev: e737217a6a960df6282653dd8db45901cd5c2994)

Change-Id: Icbcd801317c7cef7c0b5e2aeca2c73e1c48e0adb
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>