mojo_run: support parallel Android runs of mojo_run.

mojo/devtools/common/devtoolslib/linux_shell.py

Index: mojo/devtools/common/devtoolslib/linux_shell.py
diff --git a/mojo/devtools/common/devtoolslib/linux_shell.py b/mojo/devtools/common/devtoolslib/linux_shell.py
index a4a83a971a9a9fc3f4821305b9861b8076588b4c..95161e764fd90cd2fa930a028bfc1a5c81efbfcb 100644
--- a/mojo/devtools/common/devtoolslib/linux_shell.py
+++ b/mojo/devtools/common/devtoolslib/linux_shell.py
@@ -25,12 +25,12 @@ class LinuxShell(Shell):
     self.command_prefix = command_prefix if command_prefix else []
 
   @overrides(Shell)
-  def serve_local_directory(self, local_dir_path, port=0):
+  def serve_local_directory(self, local_dir_path, port=0, free_host_port=False):
     mappings = [('', [local_dir_path])]
     return 'http://%s:%d/' % http_server.start_http_server(mappings, port)
 
   @overrides(Shell)
-  def serve_local_directories(self, mappings, port=0):
+  def serve_local_directories(self, mappings, port=0, free_host_port=False):
     return 'http://%s:%d/' % http_server.start_http_server(mappings, port)
 
   @overrides(Shell)