Added set -e

Author: amraboelela

utils/android/build-toolchain

@@ -10,6 +10,8 @@
 # See https://swift.org/LICENSE.txt for license information
 # See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
+set -e
+
 cd "$(dirname $0)/../.." || exit
 SRC_DIR=$PWD