Remove unnecessary user-provided copy functions

...with the added benefit of the implementation-provided versions being trivial
and so avoiding GCC 8 -Werror=class-memaccess when these classes are subject of
memcpy/memmove in store/source/stortree.cxx and store/source/storpage.cxx.

Change-Id: I684109d8743eb7f1fa57c6925d738b11d934a7cf
Reviewed-on: https://gerrit.libreoffice.org/40977Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

store/source/storbase.hxx

@@ -179,17 +179,6 @@ struct OStorePageKey
           m_nHigh (store::htonl(nHigh))
     {}
 
-    OStorePageKey (const OStorePageKey & rhs)
-        : m_nLow (rhs.m_nLow), m_nHigh (rhs.m_nHigh)
-    {}
-
-    OStorePageKey & operator= (const OStorePageKey & rhs)
-    {
-        m_nLow  = rhs.m_nLow;
-        m_nHigh = rhs.m_nHigh;
-        return *this;
-    }
-
     /** Comparison.
      */
     bool operator== (const OStorePageKey & rhs) const
@@ -224,16 +213,6 @@ struct OStorePageLink
         std::swap(m_nAddr, rhs.m_nAddr);
     }
 
-    OStorePageLink (const OStorePageLink & rhs)
-        : m_nAddr (rhs.m_nAddr)
-    {}
-
-    OStorePageLink & operator= (const OStorePageLink & rhs)
-    {
-        m_nAddr = rhs.m_nAddr;
-        return *this;
-    }
-
     OStorePageLink & operator= (sal_uInt32 nAddr)
     {
         m_nAddr = store::htonl(nAddr);

store/source/stortree.hxx

@@ -56,20 +56,6 @@ struct OStoreBTreeEntry
           m_nAttrib (store::htonl(0))
     {}
 
-    OStoreBTreeEntry (const OStoreBTreeEntry & rhs)
-        : m_aKey    (rhs.m_aKey),
-          m_aLink   (rhs.m_aLink),
-          m_nAttrib (rhs.m_nAttrib)
-    {}
-
-    OStoreBTreeEntry& operator= (const OStoreBTreeEntry & rhs)
-    {
-        m_aKey    = rhs.m_aKey;
-        m_aLink   = rhs.m_aLink;
-        m_nAttrib = rhs.m_nAttrib;
-        return *this;
-    }
-
     /** Comparison.
     */
     enum CompareResult