fastboot: fix build break

execvpe is a GNU extension. Use execve instead.

Change-Id: I8bf4b6a4e9fd0cae0239f4c5aa9707f141460a7d
diff --git a/fastboot/fs.cpp b/fastboot/fs.cpp
index fe5cbc3..9949eae 100644
--- a/fastboot/fs.cpp
+++ b/fastboot/fs.cpp
@@ -83,7 +83,7 @@
     int status;
     pid_t child;
     if ((child = fork()) == 0) {
-        execvpe(path, const_cast<char**>(argv), const_cast<char**>(envp));
+        execve(path, const_cast<char**>(argv), const_cast<char**>(envp));
         _exit(EXIT_FAILURE);
     }
     if (child < 0) {