Use bazelisk as first choice for mvn.sh

mvn.sh should prefer bazelisk as first choice for running bazel, falling
back to the current bazel binary.

Change-Id: I5196f25d3d328f507022e589a0feeb7a67ec2bf4

tools/maven/mvn.sh

diff --git a/tools/maven/mvn.sh b/tools/maven/mvn.sh
index 6fd6341..9b05b6f 100755
--- a/tools/maven/mvn.sh
+++ b/tools/maven/mvn.sh
@@ -49,8 +49,14 @@
   set -o xtrace
 fi
 
-bazel build //tools/maven:gen_${command} || \
-  { echo "bazel failed to build gen_${command}. Use VERBOSE=1 for more info" ; exit 1 ; }
+if [[ `which bazelisk` ]]; then
+  BAZEL_CMD=bazelisk
+else
+  BAZEL_CMD=bazel
+fi
+
+${BAZEL_CMD} build //tools/maven:gen_${command} || \
+  { echo "${BAZEL_CMD} failed to build gen_${command}. Use VERBOSE=1 for more info" ; exit 1 ; }
 
 export OUTPUT_BASE=`bazel info output_base`
 ./bazel-bin/tools/maven/${command}.sh