setup.py: Add virtme-mkinitramfs to console_scripts

With this commit, virtme-mkinitramfs is installed like virtme-run and
virtme-configkernel.

Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
diff --git a/setup.py b/setup.py
index 9f7dc63..33b8a27 100755
--- a/setup.py
+++ b/setup.py
@@ -27,6 +27,7 @@
         'console_scripts': [
             'virtme-run = virtme.commands.run:main',
             'virtme-configkernel = virtme.commands.configkernel:main',
+            'virtme-mkinitramfs = virtme.commands.mkinitramfs:main',
         ]
     },
     package_data = {