python2: Remove python2 dependency from docs and dockerfiles

Dockerfile

@@ -48,7 +48,7 @@ RUN mkdir /opt/litecoin && cd /opt/litecoin \
 FROM debian:stretch-slim as builder
 
 ENV LIGHTNINGD_VERSION=master
-RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates autoconf automake build-essential git libtool python python3 python3-mako wget gnupg dirmngr git gettext
+RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates autoconf automake build-essential git libtool python3 python3-mako wget gnupg dirmngr git gettext
 
 RUN wget -q https://zlib.net/zlib-1.2.11.tar.gz \
 && tar xvf zlib-1.2.11.tar.gz \

contrib/Dockerfile.builder

@@ -24,7 +24,6 @@ RUN apt-get -qq update && \
 	libsqlite3-dev \
 	libgmp-dev \
 	git \
-	python \
 	python3 \
 	valgrind \
 	net-tools \

contrib/Dockerfile.builder.fedora

@@ -11,7 +11,6 @@ RUN dnf update -y && \
 		clang \
 		gmp-devel \
 		libsq3-devel \
-		python2-devel \
 		python3-devel \
 		python3-mako \
 		python3-pip \

contrib/linuxarm32v7.Dockerfile

@@ -48,7 +48,7 @@ RUN mkdir /opt/litecoin && cd /opt/litecoin \
 FROM debian:stretch-slim as builder
 
 ENV LIGHTNINGD_VERSION=master
-RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates autoconf automake build-essential gettext git libtool python python3 python3-mako wget gnupg dirmngr git \
+RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates autoconf automake build-essential gettext git libtool python3 python3-mako wget gnupg dirmngr git \
   libc6-armhf-cross gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf
 
 ENV target_host=arm-linux-gnueabihf

contrib/linuxarm64v8.Dockerfile

@@ -48,7 +48,7 @@ RUN mkdir /opt/litecoin && cd /opt/litecoin \
 FROM debian:stretch-slim as builder
 
 ENV LIGHTNINGD_VERSION=master
-RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates autoconf automake build-essential gettext git libtool python python3 python3-mako wget gnupg dirmngr git \
+RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates autoconf automake build-essential gettext git libtool python3 python3-mako wget gnupg dirmngr git \
   libc6-arm64-cross gcc-aarch64-linux-gnu g++-aarch64-linux-gnu
 
 ENV target_host=aarch64-linux-gnu

doc/INSTALL.md

@@ -36,7 +36,7 @@ Get dependencies:
     sudo apt-get update
     sudo apt-get install -y \
       autoconf automake build-essential git libtool libgmp-dev \
-      libsqlite3-dev python python3 python3-mako net-tools zlib1g-dev libsodium-dev \
+      libsqlite3-dev python3 python3-mako net-tools zlib1g-dev libsodium-dev \
       gettext
 
 If you don't have Bitcoin installed locally you'll need to install that
@@ -88,7 +88,6 @@ $ sudo dnf update -y && \
                 git \
                 gmp-devel \
                 libsq3-devel \
-                python2-devel \
                 python3-devel \
                 python3-pip \
                 python3-setuptools \