Use modern Python exception syntax

"except Exception as e" instead of "except Exception, e"

This is part of a transition to supporting Python 3.  Python >= 2.6
support "as" syntax.

Note: this removes Python 2.5 support.

Change-Id: I309599f3981bba2b46111c43102bee38ff132803
diff --git a/subcmds/init.py b/subcmds/init.py
index 007667e..b6b9807 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -207,7 +207,7 @@
 
     try:
       self.manifest.Link(name)
-    except ManifestParseError, e:
+    except ManifestParseError as e:
       print >>sys.stderr, "fatal: manifest '%s' not available" % name
       print >>sys.stderr, 'fatal: %s' % str(e)
       sys.exit(1)
diff --git a/subcmds/sync.py b/subcmds/sync.py
index e68a025..d16605f 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -417,7 +417,7 @@
               # in the .netrc file.
               print >>sys.stderr, 'No credentials found for %s in .netrc' % \
                                   parse_result.hostname
-            except netrc.NetrcParseError, e:
+            except netrc.NetrcParseError as e:
               print >>sys.stderr, 'Error parsing .netrc file: %s' % e
 
         if (username and password):
@@ -464,11 +464,11 @@
         else:
           print >>sys.stderr, 'error: %s' % manifest_str
           sys.exit(1)
-      except (socket.error, IOError, xmlrpclib.Fault), e:
+      except (socket.error, IOError, xmlrpclib.Fault) as e:
         print >>sys.stderr, 'error: cannot connect to manifest server %s:\n%s' % (
             self.manifest.manifest_server, e)
         sys.exit(1)
-      except xmlrpclib.ProtocolError, e:
+      except xmlrpclib.ProtocolError as e:
         print >>sys.stderr, 'error: cannot connect to manifest server %s:\n%d %s' % (
             self.manifest.manifest_server, e.errcode, e.errmsg)
         sys.exit(1)
diff --git a/subcmds/upload.py b/subcmds/upload.py
index 685e342..84a5e44 100644
--- a/subcmds/upload.py
+++ b/subcmds/upload.py
@@ -329,7 +329,7 @@
 
         branch.UploadForReview(people, auto_topic=opt.auto_topic, draft=opt.draft)
         branch.uploaded = True
-      except UploadError, e:
+      except UploadError as e:
         branch.error = e
         branch.uploaded = False
         have_errors = True
@@ -384,7 +384,7 @@
       pending_proj_names = [project.name for (project, avail) in pending]
       try:
         hook.Run(opt.allow_all_hooks, project_list=pending_proj_names)
-      except HookError, e:
+      except HookError as e:
         print >>sys.stderr, "ERROR: %s" % str(e)
         return