Core/Misc: Fix issues reported by static analysis

Fix issues reported by Coverity Scan

(cherry picked from commit 2fda1572d2)

src/server/game/Maps/Map.h

@@ -113,7 +113,7 @@ struct PositionFullTerrainStatus
         uint32 const mogpFlags;
     };
 
-    PositionFullTerrainStatus() : areaId(0), floorZ(0.0f), outdoors(true) { }
+    PositionFullTerrainStatus() : areaId(0), floorZ(0.0f), outdoors(true), liquidStatus(LIQUID_MAP_NO_WATER) { }
     uint32 areaId;
     float floorZ;
     bool outdoors;

src/server/game/Movement/Spline/Spline.h

@@ -90,7 +90,7 @@ protected:
 
 public:
 
-    explicit SplineBase() : index_lo(0), index_hi(0), m_mode(UninitializedMode), cyclic(false) { }
+    explicit SplineBase() : index_lo(0), index_hi(0), m_mode(UninitializedMode), cyclic(false), initialOrientation(0.f) { }
 
     /** Caclulates the position for given segment Idx, and percent of segment length t
         @param t - percent of segment length, assumes that t in range [0, 1]

src/server/scripts/Commands/cs_go.cpp

@@ -533,7 +533,7 @@ public:
             return true;
         }
 
-        handler->PSendSysMessage(LANG_COMMAND_GO_INSTANCE_FAILED, mapid, scriptname.c_str(), exit->target_mapId);
+        handler->PSendSysMessage(LANG_COMMAND_GO_INSTANCE_FAILED, mapid, scriptname.c_str(), exit ? exit->target_mapId : uint32(-1));
         handler->SetSentErrorMessage(true);
         return false;
     }

src/server/scripts/Northrend/Ulduar/Ulduar/boss_algalon_the_observer.cpp

@@ -1159,7 +1159,7 @@ class spell_algalon_big_bang : public SpellScript
         AfterCast += SpellCastFn(spell_algalon_big_bang::CheckTargets);
     }
 private:
-    uint32 _targetCount;
+    uint32 _targetCount = 0;
 };
 
 // 64445 - Remove Player from Phase

src/server/scripts/Northrend/Ulduar/Ulduar/boss_xt002.cpp

@@ -955,7 +955,7 @@ class spell_xt002_exposed_heart : public AuraScript
     }
 
 private:
-    uint32 _damageAmount;
+    uint32 _damageAmount = 0;
 };
 
 class achievement_nerf_engineering : public AchievementCriteriaScript