fix(Documentation/profiling): note about using the right binary

Documentation/profiling.md

@@ -3,6 +3,10 @@
 etcd exposes profiling information from the Go pprof package over HTTP.
 The basic browseable interface can be found at `http://127.0.0.1:4001/debug/pprof`.
 
+**NOTE**: In the following examples you need to ensure that the `./bin/etcd` is
+identical to the `./bin/etcd` that you are targetting (same git hash, arch,
+platform, etc).
+
 ### Heap memory profile
 
 ```