Fix dependencies in Trellis P4 STC scenario

Add steps to verify driver and pipeconf apps, as well as registered
pipeconfs. Also, start Mininet first, then push Trellis netcfg.

Change-Id: Idf52e268e6f50c7f6b8f17a5ea0390f01a607fea
diff --git a/tools/test/scenarios/net-trellis-p4-smoke.xml b/tools/test/scenarios/net-trellis-p4-smoke.xml
index 6d7a443..0ced6c1 100644
--- a/tools/test/scenarios/net-trellis-p4-smoke.xml
+++ b/tools/test/scenarios/net-trellis-p4-smoke.xml
@@ -34,4 +34,4 @@
               exec="onos-check-logs ${OC#}"/>
     </parallel>
 
-</scenario>
\ No newline at end of file
+</scenario>