tilde ~ is expanded multiple times, even if it is not part of a path

Created by: zwieberl

Reproduction: Just type touch ~/bla~

Expected behavior: Create a new file called bla~ in /home

Actual behavior:

# touch ~/bla~
touch: cannot touch ‘/home/zwieberl/bla/home/zwieberl’: No such file or directory

Build information: rustc -V: rustc 1.25.0-nightly (3ec5a99aa 2018-02-14)

./target/release/ion --version: ion 1.0.0-alpha (x86_64-unknown-linux-gnu) rev 96d5b5d2

Blocking/related: #708 (closed)