Start release increment at 1.

Per discussion in #409

This is what most distributions default to and expect.

Author: nuclearsandwich

bloom/commands/git/release.py

@@ -227,7 +227,7 @@ def process_track_settings(track_dict, release_inc_override):
     settings['ros_distro'] = track_dict['ros_distro']
     # Release increment
     if 'last_version' in track_dict and track_dict['last_version'] != version:
-        next_release_inc = str(0)
+        next_release_inc = str(1)
     else:
         next_release_inc = str(int(track_dict['release_inc']) + 1)
     settings['release_inc'] = release_inc_override or next_release_inc

bloom/config.py

@@ -190,7 +190,7 @@ def __str__(self):
     'patches': PromptEntry('Patches Directory', spec=config_spec['patches']),
     'ros_distro': PromptEntry('ROS Distro', default='indigo', spec=config_spec['ros_distro']),
     'release_repo_url': PromptEntry('Release Repository Push URL', spec=config_spec['release_repo_url']),
-    'release_inc': -1,
+    'release_inc': 0,
     'actions': [
         'bloom-export-upstream :{vcs_local_uri} :{vcs_type}'
         ' --tag :{release_tag} --display-uri :{vcs_uri}'