Fix naming of Unix packages

- .NET Core RID suffixes removed
- `el7.centos` suffix added to RPM
- `1ubuntu1.14.04.1` iteration used for DEB packages

`~` cannot be used after `ubuntu1` because GitHub release renames it to
a `.`; additionally, no packages lack the final suffix `.1`. While my
machine is `.5` I could find no packages that went past `.3`, so let's
use this to indicate that it works for `14.04.1` and forward.

We are *not* recreating the alpha.9 packages, but will we rename them
accordingly. This means that the filenames will be "correct" but the
meta-data will be out-of-date.

tools/download.sh

@@ -28,10 +28,10 @@ case "$OSTYPE" in
                 sudo apt-get install -y curl wget
                 case "$VERSION_ID" in
                     14.04)
-                        version=ubuntu.14.04-x64.deb
+                        version=ubuntu1.14.04.1_amd64.deb
                         ;;
                     16.04)
-                        version=ubuntu.16.04-x64.deb
+                        version=ubuntu1.16.04.1_amd64.deb
                         ;;
                     *)
                         exit 2 >&2 "Ubuntu $VERSION_ID is not supported!"
@@ -71,10 +71,10 @@ case "$OSTYPE" in
             ubuntu)
                 case "$VERSION_ID" in
                     14.04)
-                        $icupackage=libicu52
+                        icupackage=libicu52
                         ;;
                     16.04)
-                        $icupackage=libicu55
+                        icupackage=libicu55
                         ;;
                 esac
                 sudo apt-get install -y libunwind8 $icupackage