Description of problem:
Output of gnutls-cli contains some PK signature algorithms twice. This is caused by multiple occurrences of these algorithms in the sign_algorithms array with different OIDs (file lib/algorithms/sign.c):

static const gnutls_sign_entry sign_algorithms[] = {
        {"RSA-SHA1", SIG_RSA_SHA1_OID, GNUTLS_SIGN_RSA_SHA1, GNUTLS_PK_RSA,
         GNUTLS_DIG_SHA1, {2, 1}},
        {"RSA-SHA1", ISO_SIG_RSA_SHA1_OID, GNUTLS_SIGN_RSA_SHA1,
         GNUTLS_PK_RSA,
         GNUTLS_DIG_SHA1, {2, 1}},
        {"RSA-SHA224", SIG_RSA_SHA224_OID, GNUTLS_SIGN_RSA_SHA224,
         GNUTLS_PK_RSA,
         GNUTLS_DIG_SHA224, {3, 1}},
...
        {"DSA-SHA1", SIG_DSA_SHA1_OID, GNUTLS_SIGN_DSA_SHA1, GNUTLS_PK_DSA,
         GNUTLS_DIG_SHA1, {2, 2}},
        {"DSA-SHA1", "1.3.14.3.2.27", GNUTLS_SIGN_DSA_SHA1, GNUTLS_PK_DSA,
         GNUTLS_DIG_SHA1, {2, 2}},

...

Version-Release number of selected component (if applicable):
gnutls-3.3.24-1.el7.x86_64
gnutls-utils-3.3.24-1.el7.x86_64

How reproducible:
always

Steps to Reproduce:
# gnutls-cli -l

Actual results:
# gnutls-cli -l
<...snip...>
PK-signatures: *SIGN-RSA-SHA1*, *SIGN-RSA-SHA1*, SIGN-RSA-SHA224, SIGN-RSA-SHA256, SIGN-RSA-SHA384, SIGN-RSA-SHA512, SIGN-RSA-RMD160, *SIGN-DSA-SHA1*, *SIGN-DSA-SHA1*, SIGN-DSA-SHA224, SIGN-DSA-SHA256, *SIGN-RSA-MD5*, *SIGN-RSA-MD5*, SIGN-RSA-MD2, SIGN-ECDSA-SHA1, SIGN-ECDSA-SHA224, SIGN-ECDSA-SHA256, SIGN-ECDSA-SHA384, SIGN-ECDSA-SHA512

Expected results:
Output of gnutls-cli shouldn't contain duplicates.