Build python 3 compatibile module names

- Python 2 accepts foomodule.so as an alias for foo.so, Python 3 does
  not. Build foo.so names which works with both...

python/Makefile.am

@@ -6,16 +6,16 @@ AM_CPPFLAGS = -I$(top_builddir)/include/
 AM_CPPFLAGS += -I$(top_srcdir)/python
 AM_CPPFLAGS += -I@WITH_PYTHON_INCLUDE@
 
-pkgpyexec_LTLIBRARIES = _rpmmodule.la _rpmbmodule.la _rpmsmodule.la
+pkgpyexec_LTLIBRARIES = _rpm.la _rpmb.la _rpms.la
 pkgpyexec_DATA = rpm/__init__.py rpm/transaction.py
 
-_rpmmodule_la_LDFLAGS = -module -avoid-version -shared
-_rpmmodule_la_LIBADD = \
+_rpm_la_LDFLAGS = -module -avoid-version -shared
+_rpm_la_LIBADD = \
 	$(top_builddir)/lib/librpm.la \
 	$(top_builddir)/rpmio/librpmio.la \
 	@WITH_PYTHON_LIB@
 
-_rpmmodule_la_SOURCES = rpmmodule.c rpmsystem-py.h \
+_rpm_la_SOURCES = rpmmodule.c rpmsystem-py.h \
 	header-py.c header-py.h \
 	rpmarchive-py.c rpmarchive-py.h \
 	rpmds-py.c rpmds-py.h \
@@ -32,22 +32,22 @@ _rpmmodule_la_SOURCES = rpmmodule.c rpmsystem-py.h \
 	rpmte-py.c rpmte-py.h \
 	rpmts-py.c rpmts-py.h
 
-_rpmbmodule_la_LDFLAGS = -module -avoid-version -shared
-_rpmbmodule_la_LIBADD = \
+_rpmb_la_LDFLAGS = -module -avoid-version -shared
+_rpmb_la_LIBADD = \
 	$(top_builddir)/build/librpmbuild.la \
 	$(top_builddir)/lib/librpm.la \
 	$(top_builddir)/rpmio/librpmio.la \
 	@WITH_PYTHON_LIB@
 
-_rpmbmodule_la_SOURCES = rpmbmodule.c rpmsystem-py.h \
+_rpmb_la_SOURCES = rpmbmodule.c rpmsystem-py.h \
 	spec-py.c spec-py.h
 
-_rpmsmodule_la_LDFLAGS = -module -avoid-version -shared
-_rpmsmodule_la_LIBADD = \
+_rpms_la_LDFLAGS = -module -avoid-version -shared
+_rpms_la_LIBADD = \
         $(top_builddir)/sign/librpmsign.la \
         $(top_builddir)/lib/librpm.la \
         $(top_builddir)/rpmio/librpmio.la \
         @WITH_PYTHON_LIB@
 
-_rpmsmodule_la_SOURCES = rpmsmodule.c rpmsystem-py.h
+_rpms_la_SOURCES = rpmsmodule.c rpmsystem-py.h