services/nomad/buildbot: update config to split logs per-package

this is slightly aspirational as sometimes packages still might be built
that the solver doesn't catch but should be correct in most cases

services/nomad/build/buildbot.cfg

@@ -184,19 +184,13 @@ class ShellCommandWithChanges(steps.ShellCommand):
 
 @util.renderer
 def build_packages(props):
-    # if a better solver is written
-    # cmds = []
-    # for p in str(props.getProperty('packages')).strip().split():
-    #     cmds.append(util.ShellArg(
-    #         command=['make', f'built/{p}'],
-    #         logname=f'pkg:{p}',
-    #         haltOnFailure=True,
-    #     ))
-    cmds = [util.ShellArg(
-        command=['make', 'all'],
-        logname='build',
-        haltOnFailure=True,
-    )]
+    cmds = []
+    for p in str(props.getProperty('packages')).strip().split():
+        cmds.append(util.ShellArg(
+            command=['make', f'built/{p}'],
+            logname=f'pkg:{p}',
+            haltOnFailure=True,
+        ))
     if cmds:
         cmds.append(util.ShellArg(
             command=['make', 'clean'],