Add debug mode, activated by setting the DEBUG_REMOTEHG env var

For now, all debug mode does is to let exceptions propagate to the top
(and thus print their backtrace), while in non-debug mode, backtraces
are now suppressed. This should be a bit more user friendly.

Additionally, we get rid of one try/except pair which replaced the
potentially helpful exception message with a bland 'Repository error';
now the user can e.g. distinguish whether a 404 error occurred,
authentication failed or the domain name is unknown (due to a typo).

git-remote-hg

@@ -53,6 +53,8 @@ import time as ptime
 # Commits are modified to preserve hg information and allow bidirectionality.
 #
 
+DEBUG_REMOTEHG = os.environ.get("DEBUG_REMOTEHG") != None
+
 NAME_RE = re.compile('^([^<>]+)')
 AUTHOR_RE = re.compile('^([^<>]+?)? ?[<>]([^<>]*)(?:$|>)')
 EMAIL_RE = re.compile(r'([^ \t<>]+@[^ \t<>]+)')
@@ -426,10 +428,7 @@ def get_repo(url, alias):
             util.writefile(os.path.join(local_path, '.hg', 'sharedpath'), hg_path)
 
         repo = hg.repository(myui, local_path)
-        try:
-            peer = hg.peer(repo.ui, {}, url)
-        except:
-            die('Repository error')
+        peer = hg.peer(repo.ui, {}, url)
         repo.pull(peer, heads=None, force=True)
 
         updatebookmarks(repo, peer)
@@ -1322,4 +1321,10 @@ def bye():
         shutil.rmtree(dirname)
 
 atexit.register(bye)
-sys.exit(main(sys.argv))
+
+try:
+    sys.exit(main(sys.argv))
+except Exception, e:
+    if DEBUG_REMOTEHG:
+       raise
+    die(str(e))