[DOC] Fix details of tox

We need put a space between a param's name and a param's value in tox
and it would be more clear.
eg: from `tox -epy35` to `tox -e py35`.

Change-Id: I86750f42669bb02dcfac2b62e294d557bf44bd4c

HACKING.rst

@@ -246,7 +246,7 @@ The sample config file is autogenerated using a script. If any changes are made
 to the config variables in tempest/config.py then the sample config file must be
 regenerated. This can be done running::
 
-  tox -egenconfig
+  tox -e genconfig
 
 Unit Tests
 ----------

README.rst

@@ -172,7 +172,7 @@ of the configuration.
 You can generate a new sample tempest.conf file, run the following
 command from the top level of the Tempest directory::
 
-    $ tox -egenconfig
+    $ tox -e genconfig
 
 The most important pieces that are needed are the user ids, openstack
 endpoint, and basic flavors and images needed to run tests.
@@ -258,11 +258,11 @@ To run one single test serially ::
 
 Tox also contains several existing job configurations. For example::
 
-    $ tox -efull
+    $ tox -e full
 
 which will run the same set of tests as the OpenStack gate. (it's exactly how
 the gate invokes Tempest) Or::
 
-    $ tox -esmoke
+    $ tox -e smoke
 
 to run the tests tagged as smoke.

tempest/lib/cmd/check_uuid.py

@@ -355,7 +355,7 @@ def run():
     if errors:
         sys.exit("@decorators.idempotent_id existence and uniqueness checks "
                  "failed\n"
-                 "Run 'tox -v -euuidgen' to automatically fix tests with\n"
+                 "Run 'tox -v -e uuidgen' to automatically fix tests with\n"
                  "missing @decorators.idempotent_id decorators.")
 
 if __name__ == '__main__':