let svnversion_regenerate.sh be a source to svnversion.h to make the waf output

look prettier

wscript

@@ -720,6 +720,7 @@ def build(bld):
                 before = 'c cxx',
                 color = 'BLUE',
                 post_run = post_run,
+                source = ['svnversion_regenerate.sh'],
                 target = [bld.path.find_or_declare('svnversion.h')]
         )