Updated Makefile and tox.ini to remove duplicated package builds

Change-Id: I8a1c4b15ae408a474d342920f0df6ca626516631
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/Makefile b/Makefile
index a1cffb0..190a9b1 100644
--- a/Makefile
+++ b/Makefile
@@ -91,7 +91,6 @@
 
 package:
 	tox -e build
-	tox -e build3
 	./build-docs.sh
 
 deps:
diff --git a/tox.ini b/tox.ini
index 00326a8..ed1ef21 100644
--- a/tox.ini
+++ b/tox.ini
@@ -36,8 +36,3 @@
        setuptools-version-command
 commands = python3 setup.py --command-packages=stdeb.command bdist_deb
 
-[testenv:build3]
-basepython = python3
-deps = stdeb
-       setuptools-version-command
-commands = python3 setup.py --command-packages=stdeb.command bdist_deb