build-unit-test-docker: remove 'yamldir' option to phosphor-logging

phosphor-logging currently uses the `phosphor-dbus-interfaces.pc`
file by default to determine the location of the install YAML,
in order to generate appropriate headers for error metadata.
`phosphor-dbus-interfaces` changed where the YAML is installed, but
the yamldir value here did not match.  Remove it entirely and fall
back to obtaining the one from the pkg-config.

Tested: Ensured `phosphor-networkd` compiled using this container.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ibe2168a05e7ad5be0e497c9bcfc6cadac7607a5d
1 file changed