RFR: JDK-8283320: Error message for Windows libraries always points to --with-msvcr-dll no matter the actual file name

[Julian Waters]

TOOLCHAIN_SETUP_MSVC_DLL always points to --with-msvcr-dll if it couldn't find the requested file, even if the dll being searched for was msvcp.dll for instance. This small patch fixes the potentially confusing advice to point to the correct options

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Commit messages:
 - TOOLCHAIN_SETUP_MSVC_DLL always prints msvcr no matter the actual dll name

Changes: https://git.openjdk.java.net/jdk/pull/7853/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7853&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283320
  Stats: 5 lines in 1 file changed: 1 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7853.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7853/head:pull/7853

PR: https://git.openjdk.java.net/jdk/pull/7853