Fix case sensitive variable resolution in in memory backend

Variables are case insensitive

src/collection/backend/in_memory-per_process.cc

@@ -99,7 +99,9 @@ void InMemoryPerProcess::resolveMultiMatches(const std::string& var,
         if (x.first.at(keySize) != ':') {
             continue;
         }
-        if (x.first.compare(0, keySize, var) != 0) {
+        std::string fu = toupper(x.first);
+        std::string fvar = toupper(var);
+        if (fu.compare(0, keySize, fvar) != 0) {
             continue;
         }
         l->insert(l->begin(), new Variable(x.first, x.second));

src/collection/backend/in_memory-per_process.h

@@ -59,7 +59,7 @@ struct MyHash{
         // You might need a better hash function than this
         size_t h = 0;
         std::for_each(Keyval.begin(), Keyval.end(), [&](char c) {
-            h += c;
+            h += tolower(c);
         });
         return h;
     }