theora: Rename source files to have the same name as the headers

ext/theora/Makefile.am

@@ -1,8 +1,14 @@
 plugin_LTLIBRARIES = libgsttheora.la
 
-noinst_HEADERS = gsttheoraenc.h gsttheoradec.h gsttheoraparse.h
+noinst_HEADERS = gsttheoraenc.h \
+		 gsttheoradec.h \
+		 gsttheoraparse.h
+
+libgsttheora_la_SOURCES = gsttheora.c \
+			  gsttheoraenc.c \
+			  gsttheoradec.c \
+			  gsttheoraparse.c
 
-libgsttheora_la_SOURCES = theora.c theoraenc.c theoradec.c theoraparse.c
 libgsttheora_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_CFLAGS) $(THEORA_CFLAGS)
 libgsttheora_la_LIBADD = \
 	$(top_builddir)/gst-libs/gst/tag/libgsttag-$(GST_MAJORMINOR).la \