[SPARK-20627][PYSPARK] Drop the hadoop distirbution name from the Python version

## What changes were proposed in this pull request?

Drop the hadoop distirbution name from the Python version (PEP440 - https://www.python.org/dev/peps/pep-0440/). We've been using the local version string to disambiguate between different hadoop versions packaged with PySpark, but PEP0440 states that local versions should not be used when publishing up-stream. Since we no longer make PySpark pip packages for different hadoop versions, we can simply drop the hadoop information. If at a later point we need to start publishing different hadoop versions we can look at make different packages or similar.

## How was this patch tested?

Ran `make-distribution` locally

Author: Holden Karau <[email protected]>

Closes apache#17885 from holdenk/SPARK-20627-remove-pip-local-version-string.

Author: holdenk

dev/create-release/release-build.sh

@@ -163,9 +163,9 @@ if [[ "$1" == "package" ]]; then
     export ZINC_PORT=$ZINC_PORT
     echo "Creating distribution: $NAME ($FLAGS)"
 
-    # Write out the NAME and VERSION to PySpark version info we rewrite the - into a . and SNAPSHOT
-    # to dev0 to be closer to PEP440. We use the NAME as a "local version".
-    PYSPARK_VERSION=`echo "$SPARK_VERSION+$NAME" |  sed -r "s/-/./" | sed -r "s/SNAPSHOT/dev0/"`
+    # Write out the VERSION to PySpark version info we rewrite the - into a . and SNAPSHOT
+    # to dev0 to be closer to PEP440.
+    PYSPARK_VERSION=`echo "$SPARK_VERSION" |  sed -r "s/-/./" | sed -r "s/SNAPSHOT/dev0/"`
     echo "__version__='$PYSPARK_VERSION'" > python/pyspark/version.py
 
     # Get maven home set by MVN