phosphor-dbus-monitor: Remove unneeded RDEPENDS

We don't need to explicitly specify library dependencies as runtime
dependencies as build rules will do this automatically if they are
needed.

(From meta-phosphor rev: 3edb6cf4112f2d1c3af3e13567db1d798d3a7fb1)

Change-Id: I4cd58dd74738be27928113408e84b52a62d64af9
Signed-off-by: William A. Kennington III <wak@google.com>
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>