[Release][OSX] Verification script fails to activate conda environment

[asfimport]

Faced issue conda/conda#8186
I was using it on OSX, within tmux and zsh (probably caused by the nested shells).

Solution is to export PS1="" at https://github.com/apache/arrow/blob/master/dev/release/verify-release-candidate.sh#L236

Reporter: Krisztian Szucs / @kszucs

Related issues:

• [Release] Remove undefined variable check from verify script (is duplicated by)

_{Note: This issue was originally created as ARROW-5837. Please see the migration documentation for further details.}

[asfimport]

Kouhei Sutou / @kou:
ARROW-5820 resolved this.