RFR: 8303020: Remove carriage return in pandoc version string

[Mikael Vidstedt]

On windows/cygwin, the PANDOC_VERSION variable includes the carriage return ('\r') which makes the version check fail:

checking for pandoc version... 2.19.2
, not the recommended version 2.19.2n 2.19.2

-------------

Commit messages:
 - Fix pandoc version check on Windows

Changes: https://git.openjdk.org/jdk/pull/12696/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12696&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8303020
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12696.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12696/head:pull/12696

PR: https://git.openjdk.org/jdk/pull/12696