Don't throw exceptions when freq is off

This exception is triggered in some legitimate cases inside WSClean (reported by Bjorn A)

src/h5parm/soltab.cc

@@ -630,14 +630,9 @@ hsize_t SolTab::GetFreqIndex(double freq) const {
   if (GetAxis("freq").size == 1) {
     return 0;
   }
-  std::vector<double> freqs = GetRealAxis("freq");
-  double freq_interval = GetFreqInterval(0);
+  const std::vector<double> freqs = GetRealAxis("freq");
 
   // A full cell width before the first frequency
-  if (freq < freqs.front() - freq_interval) {
-    throw std::runtime_error("Frequency " + std::to_string(freq) +
-                             " not found in " + GetName());
-  }
   if (freq < freqs.front()) {
     return 0;
   }
@@ -653,15 +648,7 @@ hsize_t SolTab::GetFreqIndex(double freq) const {
     }
   }
 
-  // A full cell width after the last frequency
-  freq_interval = GetFreqInterval(freqs.size() - 2);
-  if (freq < freqs.back() + freq_interval) {
-    return freqs.size() - 1;
-  }
-
-  throw std::runtime_error("Frequency " + std::to_string(freq) +
-                           " not found in " + GetName());
-  return 0;
+  return freqs.size() - 1;
 }
 
 std::vector<double> SolTab::GetRealAxis(const std::string& axisname) const {