Remove 'lib' and 'swscale-error' from list of phony targets.

Both targets no longer exist.

Originally committed as revision 17951 to svn://svn.ffmpeg.org/ffmpeg/trunk

Makefile

@@ -303,4 +303,4 @@ tests/seek_test$(EXESUF): tests/seek_test.c $(FF_DEP_LIBS)
 	$(CC) $(FF_LDFLAGS) $(CFLAGS) -o $@ $< $(FF_EXTRALIBS)
 
 
-.PHONY: lib documentation *test regtest-* swscale-error zlib-error alltools check
+.PHONY: documentation *test regtest-* zlib-error alltools check