Fix a few minor undefined behavior issues.

One could have resulted in a stack smash, and the other would cause issues if we ever linked with C++ anywhere.

Author: richardjrossiii

Parse/Internal/Config/PFConfig_Private.h

@@ -11,7 +11,7 @@
 
 #import <Parse/PFConfig.h>
 
-NSString *const PFConfigParametersRESTKey;
+extern NSString *const PFConfigParametersRESTKey;
 
 @interface PFConfig (Private)
 

Parse/Internal/Installation/CurrentInstallationController/PFCurrentInstallationController.m

@@ -78,7 +78,7 @@ + (instancetype)controllerWithStorageType:(PFCurrentObjectStorageType)storageTyp
 - (BFTask *)getCurrentObjectAsync {
     @weakify(self);
     return [_dataTaskQueue enqueue:^BFTask *(BFTask *unused) {
-        return [[[BFTask taskFromExecutor:[BFExecutor defaultExecutor] withBlock:^id(BFTask *task) {
+        return [[[BFTask taskFromExecutor:[BFExecutor defaultExecutor] withBlock:^id {
             @strongify(self);
             if (self.currentInstallation) {
                 return self.currentInstallation;