DataConnection: Clear cid when entering inactive state.

Bug: 5083242

Change-Id: I0657739da54bc424433063a2244d045e47411e5f
diff --git a/telephony/java/com/android/internal/telephony/DataConnection.java b/telephony/java/com/android/internal/telephony/DataConnection.java
index 8978f1d..636646e 100644
--- a/telephony/java/com/android/internal/telephony/DataConnection.java
+++ b/telephony/java/com/android/internal/telephony/DataConnection.java
@@ -447,6 +447,7 @@
         lastFailCause = FailCause.NONE;
         mRetryOverride = -1;
         mRefCount = 0;
+        cid = -1;
 
         mLinkProperties = new LinkProperties();
         mApn = null;