feat(scripts): add more reasonable title for cherry pick PR

Before that, we used the first commit title of the main PRs and spliced
them to become the title of the cherry pick PR.

Obviously, it is more reasonable to use the titles of the main PRs and
splicing to become the title of the cherry pick PR.

scripts/cherry_pick_pull.sh

@@ -156,32 +156,6 @@ EOF
 hub pull-request -F "${prtext}" -h "${GITHUB_USER}:${NEWBRANCH}" -b "${MAIN_REPO_ORG}:${rel}"
 }
 
-function extract-subject {
-  local patch="$1"
-
-  python -c '
-import os
-import email.parser
-import email.header
-with open("'"$patch"'", "r") as f:
-    m = email.parser.Parser().parse(f, headersonly=True)
-subj = m["subject"]
-subj = email.header.decode_header(subj)
-s = u""
-for txt, enc in subj:
-    txt = txt.decode(enc) if enc else txt
-    txt = txt.decode("ascii") if isinstance(txt, bytes) else txt
-    txt = txt.replace(u"\n", u"")
-    if txt.startswith(u"[PATCH"):
-        i = txt.index(u"]")
-        txt = txt[i+1:]
-    s += txt
-s = s.strip() + u"\n"
-s = s.encode("utf-8") # write out utf-8 bytes whatsoever
-os.write(1, s)
-'
-}
-
 git checkout -b "${NEWBRANCHUNIQ}" "${BRANCH}"
 cleanbranch="${NEWBRANCHUNIQ}"
 
@@ -219,9 +193,7 @@ for pull in "${PULLS[@]}"; do
     fi
   }
 
-  # set the subject
-  subject=$(extract-subject "/tmp/${pull}.patch")
-  SUBJECTS+=("#${pull}: ${subject}")
+SUBJECTS+=("$(hub pr show -f "%i: %t" ${pull})")
 
   # remove the patch file from /tmp
   rm -f "/tmp/${pull}.patch"