[PATCH 2/2] Fix build when using GTest-1.11

[PATCH 2/2] Fix build when using GTest-1.11

Some change in GTest 1.11 headers caused a conflict on the name
`Pointer`. Removing the unconditional import of namespace `testing`
in favor of individual imports of the used items fixes it.

cc #205

Gbp-Pq: Name 0002-Fix-build-when-using-GTest-1.11.patch