Bug 1526010, NSPR 4.21 RTM, r=me

UPGRADE_NSPR_RELEASE DONTBUILD

nsprpub/TAG-INFO

@@ -1 +1 @@
-NSPR_4_21_BETA2
+NSPR_4_21_RTM

nsprpub/config/prdepend.h

@@ -10,3 +10,4 @@
  */
 
 #error "Do not include this header file."
+

nsprpub/pr/include/prinit.h

@@ -31,11 +31,11 @@ PR_BEGIN_EXTERN_C
 ** The format of the version string is
 **     "<major version>.<minor version>[.<patch level>] [<Beta>]"
 */
-#define PR_VERSION  "4.21 Beta"
+#define PR_VERSION  "4.21"
 #define PR_VMAJOR   4
 #define PR_VMINOR   21
 #define PR_VPATCH   0
-#define PR_BETA     PR_TRUE
+#define PR_BETA     PR_FALSE
 
 /*
 ** PRVersionCheck