ci: fix ci/kokoro/install/opensuse-tumbleweed (#162)

This build does not have a PR check (because it failed too often), so we
missed it in a previous PR.

Author: coryan

INSTALL.md

@@ -225,6 +225,13 @@ sudo zypper refresh && \
 sudo zypper install -y grpc-devel
 ```
 
+The following steps will install libraries and tools in `/usr/local`. By
+default pkg-config does not search in these directories.
+
+```bash
+export PKG_CONFIG_PATH=/usr/local/lib64/pkgconfig
+```
+
 #### googleapis
 
 We need a recent version of the Google Cloud Platform proto C++ libraries:

ci/kokoro/install/Dockerfile.opensuse-tumbleweed

@@ -40,6 +40,13 @@ RUN zypper refresh && \
     zypper install -y grpc-devel
 # ```
 
+# The following steps will install libraries and tools in `/usr/local`. By
+# default pkg-config does not search in these directories.
+
+# ```bash
+ENV PKG_CONFIG_PATH=/usr/local/lib64/pkgconfig
+# ```
+
 # #### googleapis
 
 # We need a recent version of the Google Cloud Platform proto C++ libraries:

ci/templates/kokoro/install/Dockerfile.opensuse-tumbleweed.in

@@ -36,4 +36,11 @@ RUN zypper refresh && \
     zypper install -y grpc-devel
 # ```
 
+# The following steps will install libraries and tools in `/usr/local`. By
+# default pkg-config does not search in these directories.
+
+# ```bash
+ENV PKG_CONFIG_PATH=/usr/local/lib64/pkgconfig
+# ```
+
 @BUILD_AND_TEST_PROJECT_FRAGMENT@