Resolves: rhbz#1647507 try inputted password as both user and owner password

Change-Id: Ibe1fae39d3153238e85400c9645766c260c9290d
Reviewed-on: https://gerrit.libreoffice.org/63081
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>
(cherry picked from commit 6ec29250)

sdext/source/pdfimport/xpdfwrapper/wrapper_gpl.cxx

@@ -101,9 +101,11 @@ int main(int argc, char **argv)
                                  : (ownerPassword[0] != '\001'
                                     ? new GooString(ownerPassword)
                                     : nullptr ) );
-    GooString* pUserPasswordStr(  userPassword[0] != '\001'
+    GooString* pUserPasswordStr( aPwBuf[0] != 0
+                                ? new GooString( aPwBuf )
+                                : (userPassword[0] != '\001'
                                   ? new GooString(userPassword)
-                                  : nullptr );
+                                  : nullptr ) );
     if( outputFile[0] != '\001' )
         g_binary_out = fopen(outputFile,"wb");