fix ExitSpan#peer bug (#12)

diff --git a/lib/skywalking/span.lua b/lib/skywalking/span.lua
index 6c5d06a..cd5ab4c 100644
--- a/lib/skywalking/span.lua
+++ b/lib/skywalking/span.lua
@@ -97,7 +97,7 @@
         injectableRef.segment_id = context.segment_id
         injectableRef.span_id = span.span_id
         -- injectableRef.network_address_id wouldn't be set. Right now, there is no network_address register mechanism
-        injectableRef.network_address = '#' .. peer
+        injectableRef.network_address = peer
 
         local entryServiceInstanceId
         local entryEndpointName