[FAB-4738] Add notes on PATH and GOROOT

As described in [FAB-4738], development environment should have PATH and
GOROOT environment variables set properly for behave tests to work.

This patchset adds some direction for them to the document for the
development environment.

Change-Id: Idd0935e89bf321c85f042e67c629f1cde60b7139
Signed-off-by: Taku Shimosawa <taku.shimosawa@hal.hitachi.com>

bddtests/README.md

@@ -62,6 +62,12 @@ make clean
 make peer
 ```
 
+The peer executable will be located in the build/bin folder. Make sure that your PATH enviroment variable contains the location.
+Execute the following command if necessary.
+```
+    export PATH=$PATH:$GOPATH/src/github.com/hyperledger/fabric/build/bin
+```
+
 The behave system also uses several docker containers.  Execute the following commands to create the required docker containers.
 
 ```

docs/source/dev-setup/devenv.rst

@@ -71,6 +71,10 @@ Make sure you have properly setup your Host's `GOPATH environment
 variable <https://github.com/golang/go/wiki/GOPATH>`__. This allows for
 both building within the Host and the VM.
 
+In case you installed Go into a different location from the standard one
+your Go distribution assumes, make sure that you also set `GOROOT
+environment variable <https://golang.org/doc/install#install>`__.
+
 Note to Windows users
 ^^^^^^^^^^^^^^^^^^^^^