Moving whitespace file up by one folder

BUG=webrtc:7030
NOTRY=True

Review-Url: https://codereview.webrtc.org/2650593004
Cr-Commit-Position: refs/heads/master@{#16245}
diff --git a/webrtc/build/whitespace.txt b/webrtc/whitespace.txt
similarity index 100%
rename from webrtc/build/whitespace.txt
rename to webrtc/whitespace.txt