Fix zsh issue in set-pythonpath.sh
Fix zsh issue in set-pythonpath.sh

When sourcing set-pythonpath.sh on a partially checked out or partially
built source tree (e.g. when running perf tests or after build errors),
an empty shell glob pattern would return an empty list in bash but
trigger an error in zsh. This would lead to the script aborting before
exporting the PYTHONPATH variable, leading to hard to debug test
failures.

To fix this, this change replaces the glob pattern with a call to
'find', which works independent of the shell being used.

Although we would only hit this in somewhat contrived edge cases, it
seems beneficial to make the code work as expected on all shells.

Testing:
I built Impala, sourced impala-config.sh in both new zsh and bash
shells, and observed that PYTHONPATH was exported correctly.

Then I deleted the .egg files in question, sourced impala-config.sh in
both new zsh and bash shells, and observed that PYTHONPATH was exported
correctly, too.

Change-Id: Ia902891ab36f3aee96a53aa105cc5775321d0058
Reviewed-on: http://gerrit.cloudera.org:8080/10901
Reviewed-by: Lars Volker <4d73c29a4561048ce85fa0051bb7a6d201781159@cloudera.com>
Tested-by: Impala Public Jenkins <039b6b20426ff68ebe492b3021890d8c8fd010c9@cloudera.com>

cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala