infra/buildbot: Add bots, add JSON "env" config variable, poll all git branches

* master.cfg: Add an "env" key to config, to store environment variables
  to set.  Has to be stored as JSON in order to be able to have the builder
  pass the envs in as a property that the build steps can access later.
  Needed for OpenBSD, where auto* commands are wrappers that redirect to
  auto*-<ver> binaries based on env.

  Add ubuntu bot.

  Scan all branches in upstream git.

  Factor out common steps, to variables that can be re-used in addSteps.

infra/buildbot/master/master.cfg

@@ -69,6 +69,16 @@ workers = {
 	  "pkg": "rpm",
 	  "cc": [ ("gcc", "4.8.5") ],
 	},
+	"ubuntu-16.10": {
+	  "os": "Ubuntu",
+	  "version": "16.10",
+	  "vm": False,
+	  "pkg": "dpkg",
+	  "cc": [
+	  	("gcc", "6.2.0"),
+	  	("tcc", "0.9.26"),
+	  ],
+	},
 	"debian-8": {
 	  "os": "Debian",
 	  "version": "8",
@@ -111,7 +121,7 @@ workers = {
 	  "vm": True,	
   	  "pkg": "",
   	  "cc": [ ("gcc", "4.2.1") ],
-  	  "latent": False,
+  	  "latent": True,
   	  "hd_image": "/var/lib/libvirt/images/openbsd-6.qcow2",
 	  "env": ' { "AUTOMAKE_VERSION": "1.15", "AUTOCONF_VERSION": "2.69" } ',
   	},
@@ -207,7 +217,8 @@ c['change_source'] = []
 c['change_source'].append(changes.GitPoller(
 	quaggagit,
         workdir='gitpoller-workdir', 
-	branches=['master','volatile/next'],
+	branches=True,
+#	branches=['master','volatile/next'],
         pollinterval=300))
 
 ####### REVISION LINKS
@@ -404,10 +415,12 @@ f.addStep(steps.RemoveDirectory(
 
 c['builders'].append(
     util.BuilderConfig(name="clang-analyzer",
-      slavenames=list(w["bot"] for w in workers.values() if not w["vm"]),
+      slavenames=list(w["bot"] for w in workers.values() if not w["vm"]
+			),
       factory=f))
 
-
+#[kw["bot"] for kw in workers if 
+		len([v for (c,v) in workers[kw]["cc"] if c == "gcc"]) > 0 ]
 ### RPM: check and build
 f = util.BuildFactory ()