Adjust documentation build dir for out of source builds

As the build dir was changed the location of CMake build files changed,
which resulted in "could not load cache" error.

Change-Id: I97d55d060bfab08ab54d1b15d9eabbede1776155
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

coin/instructions/cmake_documentation_build.yaml

@@ -1,19 +1,19 @@
 type: Group
 instructions:
   - type: ChangeDirectory
-    directory: "{{.SourceDir}}"
+    directory: "{{.SourceDir}}_build"
   # If documentation feature is present, Coin installs top-level documentation
   # built by product(qt5) build into <module_name>_doc_build/doc. Coin will
   # silently omit installing the top-level documentations if not built by the product.
   - type: ExecuteCommand
-    command: "rsync -a {{.SourceDir}}_doc_build/doc {{.SourceDir}}"
+    command: "rsync -a {{.SourceDir}}_doc_build/doc {{.SourceDir}}_build"
     maxTimeInSeconds: 300
     maxTimeBetweenOutput: 300
     userMessageOnFailure: Failed to copy top-level docs to build dir.
   # Filter list is created to exclude everything else than the
   # generated documentation from the documentation archive.
   - type: CreateFileListFromDirectory
-    directory: "{{.SourceDir}}/doc"
+    directory: "{{.SourceDir}}_build/doc"
     filterListFileName: "doc_build_filter"
     userMessageOnFailure: "Failed to create filter list for docs"
   - type: ExecuteCommand
@@ -22,7 +22,7 @@ instructions:
     maxTimeBetweenOutput: 1200
     userMessageOnFailure: Failed to generate documentation.
   - type: UploadArtifact
-    archiveDirectory: "{{.SourceDir}}/doc"
+    archiveDirectory: "{{.SourceDir}}_build/doc"
     transferType: UploadModuleDocumentation
     filterListFileName: "doc_build_filter"
     maxTimeInSeconds: 1200