main: Disable warnings from Paramiko's usage of deprecated methods

These warnings are content-free, so let's not confuse the users.

Change-Id: Ic114ca796711b8de0e377e311a25e9a34a1b8a97
diff --git a/mdt/main.py b/mdt/main.py
index 1ac739b..bb6dd6b 100755
--- a/mdt/main.py
+++ b/mdt/main.py
@@ -41,6 +41,16 @@
 from mdt import shell
 
 
+# Stop programmer's warnings about CryptographyDeprecations for silly APIs like
+# sign and verify. FIXME(jtgans): Remove this once paramiko updates their public
+# releases in Debian. See also https://github.com/paramiko/paramiko/issues/1386
+import warnings
+warnings.filterwarnings(
+    action='ignore',
+    message='.*signer and verifier have been deprecated.*',
+    module='.*paramiko.rsakey')
+
+
 MDT_USAGE_HELP = '''
 Usage: mdt <subcommand> [<options>]