Remove unusable --android flag for `mach bootstrap`

`mach` can't do any bootstrapping for Android, so the flag is useless.

python/servo/bootstrap_commands.py

@@ -136,17 +136,14 @@ def env(self):
     @CommandArgument('--interactive', "-i",
                      action='store_true',
                      help='Need to answer any (Y/n) interactive prompts.')
-    @CommandArgument('--android',
-                     action='store_true',
-                     help='Install required packages for Android')
     @CommandArgument('--force', '-f',
                      action='store_true',
                      help='Force reinstall packages')
-    def bootstrap(self, android=False, interactive=False, force=False):
+    def bootstrap(self, interactive=False, force=False):
         from servo.bootstrapper.bootstrap import Bootstrapper
 
         bootstrapper = Bootstrapper(self.context)
-        bootstrapper.bootstrap(android=android, interactive=interactive, force=force)
+        bootstrapper.bootstrap(interactive=interactive, force=force)
 
     @Command('bootstrap-rust',
              description='Download the Rust compiler',

python/servo/bootstrapper/base.py

@@ -29,14 +29,6 @@ def install_system_packages(self):
         raise NotImplementedError('%s must implement install_system_packages()' %
                                   __name__)
 
-    def install_mobile_android_packages(self):
-        '''
-        Install packages required to build Servo for Android.
-        '''
-        raise NotImplementedError('Cannot bootstrap Servo for Android: '
-                                  '%s does not yet implement install_mobile_android_packages()'
-                                  % __name__)
-
     def which(self, name):
         """Python implementation of which.
 

python/servo/bootstrapper/bootstrap.py

@@ -30,13 +30,11 @@ def __init__(self, context):
         self.instance = cls(**args)
         self.instance.context = context
 
-    def bootstrap(self, android=False, interactive=False, force=False):
+    def bootstrap(self, interactive=False, force=False):
         self.instance.interactive = interactive
         self.instance.force = force
 
-        if android:
-            self.instance.install_mobile_android_packages()
-        elif force:
+        if force:
             self.instance.install_system_packages()
         else:
             self.instance.ensure_system_packages()

python/servo/bootstrapper/windows_gnu.py

@@ -32,9 +32,6 @@ def install_system_packages(self, packages=deps):
         self._ensure_package_manager_updated()
         self.pacman_install(*packages)
 
-    def install_mobile_android_packages(self):
-        sys.exit('We do not support building Android on Windows. Sorry!')
-
     def _update_package_manager(self):
         self.pacman_update()
 

python/servo/bootstrapper/windows_msvc.py

@@ -81,6 +81,3 @@ def install_system_packages(self, packages=deps):
         with open(installed_deps_file, 'w') as installed_file:
             for line in packages:
                 installed_file.write(line + "\n")
-
-    def install_mobile_android_packages(self):
-        sys.exit('We do not support building Android on Windows. Sorry!')