[client-app] Fix benchmark script

Summary:
We weren't changing into the directory of the git repository, so running
the script from anywhere but inside the git repo didn't work. We also
weren't pulling before checking for the latest commit. Now we do both of
these things.

Test Plan: Run locally

Reviewers: spang, juan, evan

Reviewed By: evan

Differential Revision: https://phab.nylas.com/D4339

scripts/benchmark-new-commits.sh

@@ -12,12 +12,14 @@ BENCHMARK_RESULTS_DIR="$HOME/.benchmark_results"
 mkdir -p $BENCHMARK_RESULTS_DIR
 
 CWD="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
-LAST_COMMIT=$(cat $BENCHMARK_RESULTS_DIR/last_commit)
-NEXT_COMMIT=$(get_next_commit $LAST_COMMIT)
+cd $CWD/..
 
 git checkout -q master
 git pull -q --rebase
 
+LAST_COMMIT=$(cat $BENCHMARK_RESULTS_DIR/last_commit)
+NEXT_COMMIT=$(get_next_commit $LAST_COMMIT)
+
 while [[ $NEXT_COMMIT != '' ]]
 do
   echo $NEXT_COMMIT