Merge #7060: build: Make networking work inside LXC builder in gitian-building.md

3b468a0 gitian: Need `ca-certificates` and `python` for LXC builds (Wladimir J. van der Laan)
99fda26 doc: Make networking work inside builder in gitian-building.md (Wladimir J. van der Laan)

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"