dist: fix the cmake build by shipping cmake_uninstall.cmake.in too

Fixes #1755
diff --git a/Makefile.am b/Makefile.am
index 51d69d7..5aaeda5 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -30,7 +30,7 @@
  CMake/Macros.cmake              \
  CMake/CurlSymbolHiding.cmake CMake/FindCARES.cmake             \
  CMake/FindLibSSH2.cmake CMake/FindNGHTTP2.cmake                \
- CMake/FindMbedTLS.cmake
+ CMake/FindMbedTLS.cmake cmake_uninstall.cmake.in
 
 VC6_LIBTMPL = projects/Windows/VC6/lib/libcurl.tmpl
 VC6_LIBDSP = projects/Windows/VC6/lib/libcurl.dsp.dist