Add execute permission on protoc, changed after update to in 3.7.0

Change-Id: I6cc17325215cde045213c3f8bc233872cc344b90
diff --git a/packer/provision/basebuild.sh b/packer/provision/basebuild.sh
index 0e65696..abfb6ee 100644
--- a/packer/provision/basebuild.sh
+++ b/packer/provision/basebuild.sh
@@ -246,7 +246,8 @@
     unzip /tmp/protoc-${PROTOC_VERSION}-linux-x86_64.zip -d /tmp/protoc3
     mv /tmp/protoc3/bin/* /usr/local/bin/
     mv /tmp/protoc3/include/* /usr/local/include/
-    # fix permissions on include files
+    # fix permissions on files
+    chmod -R a+rx /usr/local/bin/*
     chmod -R a+r /usr/local/include/
 
     # give sudo permissions on minikube and protoc to jenkins user