Fix uninstall Makefile rule

Syntax confirmed by
https://gitlab.kitware.com/cmake/community/-/wikis/FAQ#can-i-do-make-uninstall-with-cmake

Closes GH-1187
References GH-1102 when it probably broke

cmake/cmake_uninstall.cmake.in

@@ -31,7 +31,7 @@ foreach(file ${files})
   endif()
 
   execute_process(
-    COMMAND "@CMAKE_COMMAND@" -E remove \"$ENV{DESTDIR}${file}\"
+    COMMAND "@CMAKE_COMMAND@" -E remove "$ENV{DESTDIR}${file}"
     OUTPUT_VARIABLE rm_out
     RESULT_VARIABLE rm_retval)