[fuchsia] Remove trailing newline from build_id.template.

The trailing newline in the build ID file is causing the CIPD packaging
scripts to generate packages with version tags ending in newlines.
This makes use of the CIPD command line tool because tags must be
specified verbatim, newlines and all.

This CL gets rid of that newline.

TBR=scottmg@chromium.org

Change-Id: I592a77d63ac4cb4f2c4fa09128468a9c96dc1aad
Reviewed-on: https://chromium-review.googlesource.com/1222195
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590773}

webrunner/cipd/build_id.template

@@ -1 +1 @@
-@MAJOR@.@MINOR@.@BUILD@.@PATCH@
+@MAJOR@.@MINOR@.@BUILD@.@PATCH@