Fix for numerical overflow in GeoHash

ISSUE SUMMARY

Earlier versions allowed invalid values for the min and max parameters for 2d indexes.

• min or max could be infinities or NaNs.
• min and max could be finite but too close together, leading to NaNs or infinities during index retrieval.

USER IMPACT

• The index may have invalid keys, and could return in incorrect query results

RECOVERY STEPS

• Before upgrading, drop 2d indexes.
• Upgrade to one of fixed versions (below)
• If necessary, re-create the 2d index with corrected values for the min and max parameters.

AFFECTED VERSIONS
This issue affects all supported versions at or prior to 4.4.

FIX VERSION
The fix will be included in 4.5.1, 4.0.19, 3.6.19, 4.4.0-rc7, 4.2.8