pin pip versions of email_validator and cryptography so pip doesn't keep...

pin pip versions of email_validator and cryptography so pip doesn't keep reinstalling them each upgrade even if nothing changed (and the ceffi depedency installation can be very slow and is prone to break under low memory)

setup/management.sh

@@ -7,7 +7,7 @@ echo "Installing Mail-in-a-Box system management daemon..."
 # build-essential libssl-dev libffi-dev python3-dev: Required to pip install cryptography.
 apt_install python3-flask links duplicity libyaml-dev python3-dnspython python3-dateutil \
 	build-essential libssl-dev libffi-dev python3-dev python-pip
-hide_output pip3 install --upgrade rtyaml email_validator idna cryptography boto
+hide_output pip3 install --upgrade rtyaml email_validator==1.0.0 idna>=2.0.0 cryptography==1.0 boto
 
 # duplicity uses python 2 so we need to use the python 2 package of boto
 hide_output pip install --upgrade boto

setup/questions.sh

@@ -13,7 +13,7 @@ if [ -z "$NONINTERACTIVE" ]; then
 	fi
 
 	# email_validator is repeated in setup/management.sh
-	hide_output pip3 install email_validator || exit 1
+	hide_output pip3 install email_validator==1.0.0 || exit 1
 
 	message_box "Mail-in-a-Box Installation" \
 		"Hello and thanks for deploying a Mail-in-a-Box!