fixed bug #1666873 - LZMA test segfault on Debian GNU/Linux

git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@4950 212acab6-be3b-0410-9dea-997c60f758d6

Source/Tests/decompress.cpp

@@ -20,6 +20,7 @@ extern "C" {
 #define DECOMPRESSOR(name, type, initf, dec, u)   \
   name::name() {                                  \
     vs = new type;                                \
+    memset(vs, 0, sizeof(type));                  \
   }                                               \
                                                   \
   name::~name() {                                 \