Remove no longer applicable comment regarding the "patch" package (#3789)

infra/dockerfile.commit_retrieval

@@ -4,7 +4,6 @@ ENV PATH="${PATH}:/git-cinnabar"
 
 # git is required by the annotate pipeline.
 # libcurl4 is required by git-cinnabar.
-# patch is required by the commit classifier script.
 RUN apt-get update && \
     apt-get install -y --no-install-recommends git xz-utils curl libcurl4 && \
     hg clone -r 7436689a409528730ee6a7a2a5e763c9fb821a8f https://hg.mozilla.org/hgcustom/version-control-tools /version-control-tools/ && \