pythonplugin: Rename plugin file to match plugin name

This is required by the new loader macro.

plugin/Makefile.am

-plugin_LTLIBRARIES = libgstpythonplugin.la
+plugin_LTLIBRARIES = libgstpython.la
 
 INCLUDES = $(PYGOBJECT_CFLAGS) $(GST_CFLAGS)\
 -DPYTHON_VERSION=\"$(PYTHON_VERSION)\"		\
@@ -7,7 +7,7 @@ INCLUDES = $(PYGOBJECT_CFLAGS) $(GST_CFLAGS)\
 	-DPY_LIB_SUFFIX=$(PYTHON_LIB_SUFFIX) \
 	$(PYTHON_INCLUDES)
 
-libgstpythonplugin_la_SOURCES = gstpythonplugin.c 
-libgstpythonplugin_la_LDFLAGS = -avoid-version -shrext $(PYTHON_SO)
-libgstpythonplugin_la_LIBADD =  $(PYTHON_LIBS) $(PYGOBJECT_LIBS) $(GST_LIBS)
-libgstpythonplugin_la_CFLAGS = $(GST_CFLAGS) $(PYGOBJECT_CFLAGS) $(GST_PLUGINS_BASE_CFLAGS) $(PYTHON_INCLUDES)
+libgstpython_la_SOURCES = gstpythonplugin.c
+libgstpython_la_LDFLAGS = -avoid-version -shrext $(PYTHON_SO)
+libgstpython_la_LIBADD =  $(PYTHON_LIBS) $(PYGOBJECT_LIBS) $(GST_LIBS)
+libgstpython_la_CFLAGS = $(GST_CFLAGS) $(PYGOBJECT_CFLAGS) $(GST_PLUGINS_BASE_CFLAGS) $(PYTHON_INCLUDES)

plugin/meson.build

-gst_elements_shared = shared_library('gstpythonplugin',
+gst_elements_shared = shared_library('gstpython',
     ['gstpythonplugin.c'],
     c_args : '-DHAVE_CONFIG_H -DPY_LIB_LOC=@0@'.format(pylib_loc),
     include_directories : [configinc],