gitian: Need ca-certificates and python for LXC builds

contrib/gitian-descriptors/gitian-linux.yml

@@ -15,6 +15,8 @@ packages:
 - "faketime"
 - "bsdmainutils"
 - "binutils-gold"
+- "ca-certificates"
+- "python"
 reference_datetime: "2016-01-01 00:00:00"
 remotes:
 - "url": "https://github.com/bitcoin/bitcoin.git"

contrib/gitian-descriptors/gitian-osx.yml

@@ -18,6 +18,8 @@ packages:
 - "libcap-dev"
 - "libz-dev"
 - "libbz2-dev"
+- "ca-certificates"
+- "python"
 reference_datetime: "2016-01-01 00:00:00"
 remotes:
 - "url": "https://github.com/bitcoin/bitcoin.git"

contrib/gitian-descriptors/gitian-win.yml

@@ -18,6 +18,8 @@ packages:
 - "g++-mingw-w64"
 - "nsis"
 - "zip"
+- "ca-certificates"
+- "python"
 reference_datetime: "2016-01-01 00:00:00"
 remotes:
 - "url": "https://github.com/bitcoin/bitcoin.git"