cid#1607257 Overflowed constant

this is a false positve, but perhaps we can help coverity work it
out properly with some constexpr

Change-Id: I8398153d6678585dacf4acaf7081ec32094bcda6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/174150
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

store/source/storcach.cxx

@@ -123,7 +123,7 @@ void EntryCache::destroy (Entry * entry)
 }
 
 // highbit():= log2() + 1 (complexity O(1))
-static int highbit(std::size_t n)
+static constexpr int highbit(std::size_t n)
 {
     int k = 1;
 

store/source/storcach.hxx

@@ -39,7 +39,7 @@ struct Entry;
 class PageCache :
     public store::OStoreObject
 {
-    static size_t const theTableSize = 32;
+    static size_t constexpr theTableSize = 32;
     static_assert((theTableSize & (theTableSize-1)) == 0, "table size should be a power of 2");
 
     Entry **     m_hash_table;