Test: fix false positive in HSTRLEN test.
Test: fix false positive in HSTRLEN test.

HINCRBY* tests later used the value "tmp" that was sometimes generated
by the random key generation function. The result was ovewriting what
Tcl expected to be inside Redis with another value, causing the next
HSTRLEN test to fail.

maodeyi/redis_lua,maodeyi/redis_lua,slfs007/mk-redis,spearhead-ea/redis,himoca/redis,HunanTV/redis,himoca/redis,splitice/redis,louisliangjun/redis,maodeyi/redis_lua,louisliangjun/redis,himoca/redis,HunanTV/redis,splitice/redis,ramonsnir/redis,HunanTV/redis,splitice/redis,slfs007/mk-redis,ramonsnir/redis,louisliangjun/redis,spearhead-ea/redis,HunanTV/redis,spearhead-ea/redis,ramonsnir/redis,slfs007/mk-redis,louisliangjun/redis,splitice/redis