update: disable Git fsmonitor for all Homebrew repositories

Stopping the fsmonitor doesn't seem to work, so let's just prevent the
fsmonitor from watching our repositories.

Library/Homebrew/cmd/update.sh

@@ -556,6 +556,9 @@ EOS
     [[ -d "${DIR}/.git" ]] || continue
     cd "${DIR}" || continue
 
+    # Git's fsmonitor prevents the release of our locks
+    git config --bool core.fsmonitor false
+
     if ! git config --local --get remote.origin.url &>/dev/null
     then
       opoo "No remote 'origin' in ${DIR}, skipping update!"
@@ -740,9 +743,6 @@ EOS
       merge_or_rebase "${DIR}" "${TAP_VAR}" "${UPSTREAM_BRANCH}"
       [[ -n "${HOMEBREW_VERBOSE}" ]] && echo
     fi
-
-    # Git's fsmonitor daemon will not release our lock unless we stop it.
-    git fsmonitor--daemon stop 2>/dev/null
   done
 
   if [[ -n "${HOMEBREW_INSTALL_FROM_API}" ]]