Correct initial guess for the Newton scheme in the EAGLE cooling code.

src/cooling/EAGLE/cooling.c

@@ -57,7 +57,7 @@ static const float newton_tolerance = 1.0e-4;
 static const float bisection_tolerance = 1.0e-6;
 static const float rounding_tolerance = 1.0e-4;
 static const double bracket_factor = 1.0488088481701515;    /* sqrt(1.1) */
-static const double newton_log_u_guess_cgs = 1.414213562e6; /* log10(2e12) */
+static const double newton_log_u_guess_cgs = 12.30103; /* log10(2e12) */
 
 /**
  * @brief Find the index of the current redshift along the redshift dimension