Improve logged message: cache miss

so it doesn't sound that serious like previous message
and is less generic and more easy to find in the code

Signed-off-by: Szymon Kłos <szymon.klos@collabora.com>
Change-Id: I3eb746af8aef39b566d3213ab2935372219e8d98

wsd/TileCache.cpp

@@ -234,7 +234,7 @@ bool TileCache::getTextStream(StreamType type, const std::string& fileName, std:
     {
         // This is not an error because the first time
         // we lookup a file, it won't be in the cache.
-        LOG_INF("Could not open " << fileName);
+        LOG_INF("Cache miss, could not find text stream: " << fileName);
         return false;
     }