[CI] skip arvo download, retrieve pill directly

.travis.yml

@@ -15,10 +15,6 @@ before_install:
 install:
   # pwd: ~/urbit
   - pip3 install --user -I meson==0.44.1
-  - git clone https://github.com/urbit/arvo
-  - cd ./arvo
-  - git checkout $(cat ../.travis/pin-arvo-commit.txt)
-  - cd ..
 
 script:
   - meson . ./build --buildtype=debugoptimized -Dgc=true -Dprof=true

.travis/test.js

@@ -1,11 +1,15 @@
 'use strict';
 
+var fs      = require('fs')
 var runner  = require('urbit-runner')
 var Urbit   = runner.Urbit;
 var ERROR   = runner.ERROR;
 var actions = runner.actions
 
-var args  = ['-A', '../arvo', '-csgPSF', 'zod', 'zod'];
+var hash  = fs.readFileSync('./pin-arvo-commit.txt', 'utf-8').slice(0, 10)
+var pill  = 'https://bootstrap.urbit.org/git-' + hash + '.pill'
+
+var args  = ['-u', pill, '-cgPSF', 'zod', 'zod'];
 var urbit = new Urbit(args);
 
 // vere hangs (always?) with run in travis-ci with -P