Fix bug in linker environment variable lookup.

The linker_env_get() method that is used to match an environment
variable was failing due to an incorrect equality check.

This  was introduced in git change
be5755969d.

The bug was causing the linker to ignore environment variables such
as LD_LIBRARY_PATH. This issue also affects the linker_env_secure()
path that removes unsafe environment variables, since it would
not match any in the unsecure variable list.

Change-Id: I14228df9252010e9fb4c1862bed5735f23e97aec

linker/linker_environ.c

@@ -110,7 +110,7 @@ env_match(char* envstr, const char* name)
     while (envstr[cnt] == name[cnt] && name[cnt] != '\0')
         cnt++;
 
-    if (name[cnt] != '\0' && envstr[cnt] == '=')
+    if (name[cnt] == '\0' && envstr[cnt] == '=')
         return envstr + cnt + 1;
 
     return NULL;