Update the gitingore file and tox.ini

1.update the gitingore file for .swp.
2.delete the no need line before build the docs in tox.ini.

Change-Id: I64b9da411a902a9cedf90d69f59e3d32cc1913e1

.gitignore

@@ -45,3 +45,6 @@ ChangeLog
 etc/*.conf
 tools/lintstack.head.py
 tools/pylint_exceptions
+
+#Linux swap file
+*.swp

tox.ini

@@ -39,10 +39,7 @@ commands =
 commands = {posargs}
 
 [testenv:docs]
-commands =
-    rm -rf doc/html doc/build
-    rm -rf doc/source/apidoc doc/source/api
-    python setup.py build_sphinx
+commands = python setup.py build_sphinx
 
 [testenv:pylint]
 setenv = VIRTUAL_ENV={envdir}