ICU-20625 Fixing uninitialized memory in DTPG detected by Valgrind.
diff --git a/icu4c/source/i18n/dtptngen.cpp b/icu4c/source/i18n/dtptngen.cpp
index 8128d67..4616131 100644
--- a/icu4c/source/i18n/dtptngen.cpp
+++ b/icu4c/source/i18n/dtptngen.cpp
@@ -2547,7 +2547,8 @@
 }
 
 
-PtnSkeleton::PtnSkeleton() {
+PtnSkeleton::PtnSkeleton()
+    : addedDefaultDayPeriod(FALSE) {
 }
 
 PtnSkeleton::PtnSkeleton(const PtnSkeleton& other) {
@@ -2558,6 +2559,7 @@
     uprv_memcpy(type, other.type, sizeof(type));
     original.copyFrom(other.original);
     baseOriginal.copyFrom(other.baseOriginal);
+    addedDefaultDayPeriod = other.addedDefaultDayPeriod;
 }
 
 void PtnSkeleton::clear() {