Fix SIGPIPE in dpkg-deb content checks

With set -o pipefail, grep -q exits immediately on first match,
causing dpkg-deb to receive SIGPIPE and return non-zero. This made
the pipeline fail even when the pattern was found. The effect was
position-dependent: patterns matching early entries (usr/bin/) always
failed, while later entries (usr/share/man/) sometimes succeeded
because dpkg-deb finished writing before grep exited.

Fix by using grep >/dev/null instead of grep -q, which keeps reading
the pipe until dpkg-deb finishes naturally.

Also remove debug output from previous commits.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: madeye

tests/test_deb_build.sh

@@ -40,7 +40,8 @@ check_fail() {
 # Verifies that at least one file matching PATTERN exists in the .deb
 check_file_in_deb() {
     local deb="$1" pattern="$2" desc="$3"
-    if dpkg-deb -c "$deb" | grep -qE "$pattern"; then
+    # Avoid grep -q: with pipefail, early grep exit causes SIGPIPE on dpkg-deb
+    if dpkg-deb -c "$deb" | grep -E "$pattern" >/dev/null; then
         check_pass "$desc"
     else
         check_fail "$desc"
@@ -123,12 +124,6 @@ if [ "$FAIL_COUNT" -gt 0 ]; then
 fi
 
 # Main package: binaries
-echo "  DEBUG: DEB_MAIN=$DEB_MAIN"
-ls -la "$DEB_MAIN" || true
-echo "  DEBUG: dpkg-deb --info:"
-dpkg-deb --info "$DEB_MAIN" 2>&1 | head -10 || true
-echo "  DEBUG: dpkg-deb -c (stderr+stdout) first 30 lines:"
-dpkg-deb -c "$DEB_MAIN" 2>&1 | head -30 || true
 for bin in ss-local ss-server ss-redir ss-tunnel ss-manager; do
     check_file_in_deb "$DEB_MAIN" "usr/bin/${bin}" "$bin binary in main package"
 done