[FAB-4948] Fix text in samples doc

Change "retrieves the three" to
"retrieves four" since there are
actually four binaries listed

Change-Id: Ia9140cf9285d59568cd093eb86765565dcbc6748
Signed-off-by: Gari Singh <gari.r.singh@gmail.com>

docs/source/samples.rst

@@ -28,7 +28,7 @@ To do this, execute the following command:
 The curl command above downloads and executes a bash script
 that will download and extract all of the platform-specific binaries you
 will need to set up your network and place them into the cloned repo you
-created above. It retrieves the three platform-specific binaries:
+created above. It retrieves four platform-specific binaries:
   * ``cryptogen``,
   * ``configtxgen``,
   * ``configtxlator``, and