hgweb.cgi and hgwebdir.cgi fixes/cleanups for user configurable parts:

- "import os" was missing in hgwebdir.cgi, added to comments for both script.
- HGENCODING has to be set before importing hgweb, otherwise you'll get
  mixed encoding in changelog vs. file content/diffs.
- "import sys" is only needed when changing sys.path
- document purpose of cgitb.

hgweb.cgi

@@ -2,20 +2,25 b''
 #
 # An example CGI script to use hgweb, edit as necessary
 
-import cgitb, os, sys
+# send python tracebacks to the browser if an error occurs:
+import cgitb
 cgitb.enable()
 
-# sys.path.insert(0, "/path/to/python/lib") # if not a system-wide install
-from mercurial.hgweb.hgweb_mod import hgweb
-from mercurial.hgweb.request import wsgiapplication
-import mercurial.hgweb.wsgicgi as wsgicgi
+# adjust python path if not a system-wide install:
+#import sys
+#sys.path.insert(0, "/path/to/python/lib")
 
 # If you'd like to serve pages with UTF-8 instead of your default
 # locale charset, you can do so by uncommenting the following lines.
 # Note that this will cause your .hgrc files to be interpreted in
 # UTF-8 and all your repo files to be displayed using UTF-8.
 #
-# os.environ["HGENCODING"] = "UTF-8"
+#import os
+#os.environ["HGENCODING"] = "UTF-8"
+
+from mercurial.hgweb.hgweb_mod import hgweb
+from mercurial.hgweb.request import wsgiapplication
+import mercurial.hgweb.wsgicgi as wsgicgi
 
 def make_web_app():
     return hgweb("/path/to/repo", "repository name")

hgwebdir.cgi

@@ -2,10 +2,22 b''
 #
 # An example CGI script to export multiple hgweb repos, edit as necessary
 
-import cgitb, sys
+# send python tracebacks to the browser if an error occurs:
+import cgitb
 cgitb.enable()
 
-# sys.path.insert(0, "/path/to/python/lib") # if not a system-wide install
+# adjust python path if not a system-wide install:
+#import sys
+#sys.path.insert(0, "/path/to/python/lib")
+
+# If you'd like to serve pages with UTF-8 instead of your default
+# locale charset, you can do so by uncommenting the following lines.
+# Note that this will cause your .hgrc files to be interpreted in
+# UTF-8 and all your repo files to be displayed using UTF-8.
+#
+#import os
+#os.environ["HGENCODING"] = "UTF-8"
+
 from mercurial.hgweb.hgwebdir_mod import hgwebdir
 from mercurial.hgweb.request import wsgiapplication
 import mercurial.hgweb.wsgicgi as wsgicgi
@@ -25,17 +37,10 b' import mercurial.hgweb.wsgicgi as wsgicg'
 #   [collections]
 #   /foo = /foo
 # Then repos will list as bar and quux/baz.
-
+#
 # Alternatively you can pass a list of ('virtual/path', '/real/path') tuples
 # or use a dictionary with entries like 'virtual/path': '/real/path'
 
-# If you'd like to serve pages with UTF-8 instead of your default
-# locale charset, you can do so by uncommenting the following lines.
-# Note that this will cause your .hgrc files to be interpreted in
-# UTF-8 and all your repo files to be displayed using UTF-8.
-#
-# os.environ["HGENCODING"] = "UTF-8"
-
 def make_web_app():
     return hgwebdir("hgweb.config")