Change the interactive_mode environment variable from string to boolean

It was confusing to test on a string but passing a boolean as the default
value.

README.adoc

@@ -32,7 +32,7 @@ Those are global project parameters mandatory to Drupalizer.
 |Project root directory.
 
 |_interactive_mode_
-|If false, no prompt. Useful for Jenkins.
+|If False, no prompt. Useful for Jenkins.
 
 |_locale_
 |If True, install the site in French.

docker.py

@@ -141,7 +141,7 @@ def container_start(role='local'):
                 # If container was successful build, get the IP address and show it to the user.
                 env.container_ip = h.fab_run(role, 'docker inspect -f "{{{{.NetworkSettings.IPAddress}}}}" '
                                              '{}_container'.format(env.project_name), capture=True)
-                if env.get('interactive_mode', True) != 'false':
+                if env.get('interactive_mode', True):
                     h.fab_update_hosts(env.container_ip, env.site_hostname)
 
                     print(green('Docker container {}_container was build successful. '
@@ -165,7 +165,7 @@ def container_stop(role='local'):
     """
     with h.fab_cd(role, env.workspace):
         if '{}_container'.format(env.project_name) in docker_ps():
-            if env.get('interactive_mode', True) != 'false':
+            if env.get('interactive_mode', True):
                 h.fab_remove_from_hosts(env.site_hostname)
             h.fab_run(role, 'docker stop {}_container'.format(env.project_name))
             print(green('Docker container {}_container was successful stopped'.format(env.project_name)))
@@ -183,7 +183,7 @@ def container_remove(role='local'):
     with h.fab_cd(role, env.workspace):
         if '{}_container'.format(env.project_name) in docker_ps():
 
-            if env.get('interactive_mode', True) != 'false':
+            if env.get('interactive_mode', True):
                 h.fab_remove_from_hosts(env.site_hostname)
             
             h.fab_run(role, 'docker rm -f {}_container'.format(env.project_name))

drush.py

@@ -50,20 +50,19 @@ def make(action='install'):
         drush_opts += "--contrib-destination=profiles/{} ".format(env.site_profile)
         h.update_profile()
 
-    if env.get('interactive_mode', True) == 'false':
+    if not env.get('interactive_mode', True):
         drush_opts += "--translations=fr "
     elif confirm(red('Say [Y] to {} the site at {} with the French translation, if you say [n] '
                      'the site will be installed in English only'.format(action, env.site_root))):
         drush_opts += "--translations=fr "
 
-    if env.get('interactive_mode', True) != 'false':
+    if env.get('interactive_mode', True):
         drush_opts += " --working-copy --no-gitinfofile"
     if not h.fab_exists('local', env.site_root):
         h.fab_run('local', "mkdir {}".format(env.site_root))
     with h.fab_cd('local', env.site_root):
         h.fab_run('local', 'drush make {} {} -y'.format(drush_opts, env.makefile))
 
-
 @task
 @roles('local')
 def aliases():