Both names exist, so put back the correct file names

Author: bmribler

downloads/hdf4/hdf4_3_1.md

@@ -21,8 +21,8 @@ Applications that were created with earlier HDF4 releases AND employed internal
 
 |  File  |  Type |
 | ----- | ---- | --------------------- |
-| [hdf4.3.1.tar.gz](https://github.com/HDFGroup/hdf4/releases/download/hdf4.3.1/hdf.tar.gz) | Source release   |
-| [hdf4.3.1.zip](https://github.com/HDFGroup/hdf4/releases/download/hdf4.3.1/hdf.zip) | Source release    |
+| [hdf4.3.1.tar.gz](https://github.com/HDFGroup/hdf4/releases/download/hdf4.3.1/hdf4.3.1.tar.gz) | Source release   |
+| [hdf4.3.1.zip](https://github.com/HDFGroup/hdf4/releases/download/hdf4.3.1/hdf4.3.1.zip) | Source release    |
 | [Ready to use Binaries](https://github.com/HDFGroup/hdf4/releases/tag/hdf4.3.1)  | Pre-built binary distributions for Unix and Windows |
 | [sha256](https://github.com/HDFGroup/hdf4/releases/download/hdf4.3.1/hdf4.3.1.sha256sums.txt) | Checksum file   |