fix(build): pin OVN to specific commit for reproducible builds (#6335)

Clone with depth=10 and checkout a specific commit to ensure
reproducible builds and avoid picking up unexpected changes from
the branch-24.03 branch tip.

Signed-off-by: Mengxin Liu <liumengxinfly@gmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: oilbeater

dist/images/Dockerfile.base

@@ -61,8 +61,9 @@ RUN cd /usr/src/ && \
     # update ovs-sandbox for docker run
     git apply $SRC_DIR/54b767822916606dbb78335a3197983f435b5b8a.patch
 
-RUN cd /usr/src/ && git clone -b branch-24.03 --depth=1 https://github.com/ovn-org/ovn.git && \
+RUN cd /usr/src/ && git clone -b branch-24.03 --depth=10 https://github.com/ovn-org/ovn.git && \
     cd ovn && \
+    git checkout ef8f5c1ac63e8094eaf13507013e310991db45a2 && \
     # change hash type from dp_hash to hash with field src_ip
     git apply $SRC_DIR/e490f5ac0b644101913c2a3db8e03d85e859deff.patch && \
     # modify src route priority