DRTVWR-418, MAINT-7038: Don't add double quotes to channel name.

The CMake directive that passes VIEWER_CHANNEL to the C++ compiler as
LL_VIEWER_CHANNEL was enclosing the VIEWER_CHANNEL value in double quotes. At
this point in history, those double quotes literally become part of the
LL_VIEWER_CHANNEL value, causing the viewer to construct a bad Viewer Version
Manager query containing those double quotes. Removing them fixes the query.

indra/cmake/BuildVersion.cmake

@@ -54,7 +54,7 @@ if (NOT DEFINED VIEWER_SHORT_VERSION) # will be true in indra/, false in indra/n
     endif ("${VIEWER_VERSION_REVISION}" STREQUAL "")
 
     set(VIEWER_CHANNEL_VERSION_DEFINES
-        "LL_VIEWER_CHANNEL=\"${VIEWER_CHANNEL}\""
+        "LL_VIEWER_CHANNEL=${VIEWER_CHANNEL}"
         "LL_VIEWER_VERSION_MAJOR=${VIEWER_VERSION_MAJOR}"
         "LL_VIEWER_VERSION_MINOR=${VIEWER_VERSION_MINOR}"
         "LL_VIEWER_VERSION_PATCH=${VIEWER_VERSION_PATCH}"