Improve viewvc-install's response to invalid arguments.

* viewvc-install: Move introductory info printing after argument passing, so
    that it is not shown if there is an argument parsing error.
  Catch GetoptError, and report nicely.
  Do not pass None to getopt where it wants a string.


git-svn-id: http://viewvc.tigris.org/svn/viewvc/trunk@1293 8cb11bc2-c004-0410-86c3-e597b4017df7

viewvc-install

@@ -283,16 +283,20 @@ def install_tree(src_path, dst_path, prompt_replace):
 
 ## MAIN
 if __name__ == "__main__":
-    print INFO_TEXT
-
     # option parsing
-    optlist, args = getopt.getopt(sys.argv[1:], None, ['prefix=', 'destdir='])
+    try:
+      optlist, args = getopt.getopt(sys.argv[1:], "", ['prefix=', 'destdir='])
+    except getopt.GetoptError, e:
+      Error("Invalid option", getopt.GetoptError, e)
     for opt, arg in optlist:
       if opt == '--prefix':
         ROOT_DIR = arg
       if opt == '--destdir':
         DESTDIR = arg
 
+    ## print greeting
+    print INFO_TEXT
+
     ## prompt for ROOT_DIR if none provided
     if ROOT_DIR is None:
       if sys.platform == "win32":