veyron/services/wspr/wsrpd/lib: fix build breakage

Change-Id: I7a4011a920191c196db5182df88c91f8840f2f64
diff --git a/services/wspr/wsprd/lib/server.go b/services/wspr/wsprd/lib/server.go
index 5fd89bf..901287e 100644
--- a/services/wspr/wsprd/lib/server.go
+++ b/services/wspr/wsprd/lib/server.go
@@ -163,7 +163,7 @@
 		return nil, nil, fmt.Errorf("no dispatcher registered for %q, from %q", name, suffix)
 	} else {
 		suffix = strings.TrimLeft(suffix, "/")
-		suffix = strings.TrimPrefix(suffix, name[0])
+		suffix = strings.TrimPrefix(suffix, name)
 		suffix = strings.TrimLeft(suffix, "/")
 		return disp.Lookup(suffix)
 	}