[Dispatcher] DiffbrowsersTask and DiffenatorTask: UNKNOWN: Not found family by name "Solway"

[graphicore]

Currently, the family "Solway" is in google/fonts master git but not available via the google fonts production api (gives "Page not found" at the moment)

In the dispatcher this leaves to a badly handled error:

i.e. for Task: Diffbrowsers

Method: activate failed

Error: 2 UNKNOWN: Not found family by name "Solway"
    at Object.exports.createStatusError (/var/javascript/node_modules/grpc/src/common.js:91:15)
    at Object.onReceiveStatus (/var/javascript/node_modules/grpc/src/client_interceptors.js:1204:28)
    at InterceptingListener._callNext (/var/javascript/node_modules/grpc/src/client_interceptors.js:568:42)
    at InterceptingListener.onReceiveStatus (/var/javascript/node_modules/grpc/src/client_interceptors.js:618:8)
    at callback (/var/javascript/node_modules/grpc/src/client_interceptors.js:845:24)

The error should be handled gracefully and give a clear descriprion.

[graphicore]

Related #118 #120

[graphicore]

Fixed in 62d5a14