Use HTTP instead of FTP to transfer the xulrunner package when building staff client

Use HTTP instead of FTP to transfer the xulrunner package when building staff client

When building staff clients, using FTP seems to result in the xulrunner
packages not being found.

Connecting to ftp.mozilla.org (ftp.mozilla.org)|63.245.215.46|:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done.    ==> PWD ... done.
==> TYPE I ... done.  ==> CWD (1) /pub/mozilla.org/xulrunner/releases/14.0.1/runtimes ... done.
==> SIZE xulrunner-14.0.1.en-US.win32.zip ... 17646249
==> PASV ... done.    ==> RETR xulrunner-14.0.1.en-US.win32.zip ...
No such file ‘xulrunner-14.0.1.en-US.win32.zip’.

This patch makes the staff client build scripts use http to grab the file, instead.

Signed-off-by: Michael Peters <mpeters@emeralddata.net>