Revert "clang plugin for push_back after using sized constructor"

This reverts commit e2fa592c, sould no longer be
necessary after 3be8c4c2 "The badvectorinit
plug-in probably can be retired".

Change-Id: I26fadaf002e8e21144a7e888a80bb40eb017a64b
Reviewed-on: https://gerrit.libreoffice.org/30296Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
Tested-by: Stephan Bergmann <sbergman@redhat.com>

filter/source/msfilter/mscodec.cxx

@@ -364,8 +364,7 @@ void MSCodec_CryptoAPI::InitKey (
     sal_uInt32 saltSize = 16;
 
     // Prepare initial data -> salt + password (in 16-bit chars)
-    std::vector<sal_uInt8> initialData;
-    initialData.insert(initialData.begin(), pDocId, pDocId + saltSize);
+    std::vector<sal_uInt8> initialData(pDocId, pDocId + saltSize);
 
     // Fill PassData into KeyData.
     for (sal_Int32 nInd = 0; nInd < 16 && pPassData[nInd]; ++nInd)