Fix 5 issues reported by PVS studio

* src/sky.cpp  146     warn    V519 The 'suncolor_f.r' variable is assigned values twice successively. Perhaps this is a mistake. Check lines: 142, 146.
* src/sky.cpp  147     warn    V519 The 'suncolor_f.g' variable is assigned values twice successively. Perhaps this is a mistake. Check lines: 143, 147.
* src/sky.cpp  148     warn    V519 The 'suncolor_f.b' variable is assigned values twice successively. Perhaps this is a mistake. Check lines: 144, 148.
* src/threading/thread.cpp     63      err     V730 Not all members of a class are initialized inside the constructor. Consider inspecting: m_thread_obj.
* src/server.cpp       3243    err     V595 The 'log' pointer was utilized before it was verified against nullptr. Check lines: 3243, 3258.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/server.cpp b/src/server.cpp
index e0a15ab87..5bdf22c7e 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -3237,7 +3237,8 @@ bool Server::rollbackRevertActions(const std::list<RollbackAction> &actions,
 	ServerMap *map = (ServerMap*)(&m_env->getMap());
 
 	// Fail if no actions to handle
-	if(actions.empty()){
+	if (actions.empty()) {
+		assert(log);
 		log->push_back("Nothing to do.");
 		return false;
 	}