Allow download of compressed attachments.

Assuming all compressed files are malware is a little extreme.

Change-Id: I0ef776f3ad4af1fb73199989c99ab05171353d17

emailcommon/src/com/android/emailcommon/utility/AttachmentUtilities.java

@@ -111,8 +111,6 @@ public class AttachmentUtilities {
         "hta", "ins", "isp", "jse", "lib", "mde", "msc", "msp",
         "mst", "pif", "scr", "sct", "shb", "sys", "vb", "vbe",
         "vbs", "vxd", "wsc", "wsf", "wsh",
-        // File types of common compression/container formats (again, to avoid malware)
-        "zip", "gz", "z", "tar", "tgz", "bz2",
     };
     /**
      * Filename extensions of attachments that can be installed.