python-packages: Clean up Makefiles

This removes:

* Python 3 variants (VARIANT:=python3)

* "for Python3" from package titles

* Package selection condition from package dependencies, e.g.
  +PACKAGE_python3-six:python3-light replaced with +python3-light

* "Default" package information sections, e.g.
  Package/python-six/Default removed and package details merged into
  Package/python3-six

* "(Variant for Python3)" from package descriptions

Signed-off-by: Jeffery To <jeffery.to@gmail.com>

lang/python/ruamel-yaml/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=ruamel-yaml
 PKG_VERSION:=0.15.100
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PYPI_NAME:=ruamel.yaml
 PKG_HASH:=8e42f3067a59e819935a2926e247170ed93c8f0b2ab64526f888e026854db2e4
@@ -22,25 +22,18 @@ include ../pypi.mk
 include $(INCLUDE_DIR)/package.mk
 include ../python3-package.mk
 
-define Package/ruamel-yaml/Default
+define Package/python3-ruamel-yaml
   SECTION:=lang
   CATEGORY:=Languages
   SUBMENU:=Python
   TITLE:=YAML 1.2 loader/dumper package for Python
   URL:=https://bitbucket.org/ruamel/yaml
-endef
-
-define Package/python3-ruamel-yaml
-$(call Package/ruamel-yaml/Default)
   DEPENDS:= \
-      +PACKAGE_python3-ruamel-yaml:python3-light
-  VARIANT:=python3
+      +python3-light
 endef
 
 define Package/python3-ruamel-yaml/description
 ruamel-yaml is a YAML parser/emitter that supports roundtrip preservation of comments, seq/map flow style, and map key order
-.
-(Variant for Python3)
 endef
 
 $(eval $(call Py3Package,python3-ruamel-yaml))