Removed dependency on jq in test #175.

If the machine coordinating the test runs does not have jq, then test #175 fails with:
> test #1 "weave_on test-0.lon1.weave-net report | jq -r '.Router.Targets[] | tostring' | sort" failed:
>     expected "test-1.lon1.weave-net
> test-2.lon1.weave-net"
>     got nothing
This change completely removes the dependency on jq to make the test more robust and avoid potential confusion.

test/175_target_peer_persistence_3_test.sh

@@ -7,7 +7,7 @@ assert_targets() {
     HOST=$1
     shift
     EXPECTED=$(for TARGET in $@; do echo $TARGET; done | sort)
-    assert "weave_on $HOST report | jq -r '.Router.Targets[] | tostring' | sort" "$EXPECTED"
+    assert "weave_on $HOST report -f '{{range .Router.Targets}}{{.}}{{\"\n\"}}{{end}}' | sort" "$EXPECTED"
 }
 
 start_suite "Check Docker restart uses persisted peer list"