Fix presubmit script.

tools/ci/linux/presubmit.sh

diff --git a/tools/ci/linux/presubmit.sh b/tools/ci/linux/presubmit.sh
index c0d4f6e..6377a37 100755
--- a/tools/ci/linux/presubmit.sh
+++ b/tools/ci/linux/presubmit.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-BUILDROOT=${BUILDROOT:-github/istioApigeeAdapter}
+BUILDROOT=${BUILDROOT:-git/istioApigeeAdapter}
 export BUILDROOT
 
 (cd ${BUILDROOT}; make presubmit)