MXS-1220: Compare headers case-insensitively

The header names are not case sensitive.

server/core/admin.cc

@@ -55,7 +55,7 @@ int kv_iter(void *cls,
 {
     size_t* rval = (size_t*)cls;
 
-    if (strcmp(key, "Content-Length") == 0)
+    if (strcasecmp(key, "Content-Length") == 0)
     {
         *rval = atoi(value);
         return MHD_NO;

server/core/maxscale/httprequest.hh

@@ -36,7 +36,7 @@ static int value_iterator(void *cls,
 {
     std::pair<std::string, std::string>* cmp = (std::pair<std::string, std::string>*)cls;
 
-    if (cmp->first == key)
+    if (strcasecmp(cmp->first.c_str(), key) == 0)
     {
         cmp->second = value;
         return MHD_NO;