Fixes for testRmanOslParser

Set RMAN_SHADERPATH to the location of the OSL shaders used
by the test. These are typically found automatically by the
rmanDiscovery plugin by looking relative to the hdPrmanLoader
plugin, which is installed in <inst>/plugin. However, in the
monolithic build this plugin is embedded in the single shared
library, which is installed in <inst>/lib. This breaks the
automatic discovery, so we need to hard-code the path to
the shaders instead.

Also remove unnecessary quotes from env setting; these quotes
were being passed all the way through to rmanDiscovery causing
incorrect search paths.

Fixes #1396

(Internal change: 2131436)

third_party/renderman-23/plugin/rmanOslParser/CMakeLists.txt

@@ -27,8 +27,15 @@ pxr_plugin(rmanOslParser
         plugInfo.json
 )
 
-# Need to set RMANTREE environment variable when running tests.
+# Need to set RMANTREE and RMAN_SHADERPATH environment variable when running
+# tests.
+#
+# XXX: RMAN_SHADERPATH is only necessary for the monolithic build; in all
+# other cases, the shaders accessed by the test are automatically found
+# relative to libHdPrmanLoader. We may be able to remove this if we made
+# it so this library wasn't embedded in the monolithic library.
 get_filename_component(RMANTREE_PATH "${RENDERMAN_INCLUDE_DIR}/.." ABSOLUTE)
+get_filename_component(RMANSHADER_PATH "${CMAKE_INSTALL_PREFIX}/plugin/usd/resources/shaders" ABSOLUTE)
 
 pxr_test_scripts(
     testenv/testRmanOslParser.py
@@ -39,6 +46,7 @@ pxr_register_test(testRmanOslParser
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testRmanOslParser"
     EXPECTED_RETURN_CODE 0
     ENV
-      RMANTREE="${RMANTREE_PATH}"
+      RMANTREE=${RMANTREE_PATH}
+      RMAN_SHADERPATH=${RMANSHADER_PATH}
 )